Weeds, prints and (butter)flies

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A week in and out of the garden

After a few non-gardening days last week with family coming to stay, I returned to volunteer at Osterley, to find that an interloper had arrived in the vegetable bed in the Tudor Walled Garden that we had thoroughly weeded a week earlier. Numerous substantial seedlings of gallant soldier had pioneered their way along the aubergine and chilli pepper rows. Gallant soldier is a corruption of this plant’s scientific name Galinsoga parviflora, a member of the daisy family which bears very small white flowers amidst serrated oval leaves.

I’ve got a new plant identifier app on my phone, Flora incognita, which swiftly identified the vigorous invader. Subsequent reading reveals other common names for this fast reproducing plant: quickweed, potato weed and (my favourite) galloping soldier. It was originally collected in its native Peru in 1796 and brought to Kew Gardens, from whence it escaped, earning the moniker the Kew weed! There’s a delicious description in William Edmondes’ ‘Weeds Weeding (& Darwin): The Gardener’s Guide‘, my weed bible, of the prolific Galinsoga parviflora being brought to Kew Gardens and ‘almost immediately galloping away down the street and all over London’. This conjures a vision of it heading north along Kew Road and marching across Kew Bridge to Brentford, with a breakaway battalion hopping onto the District Line to spread across the city.

We made short shrift of the energetic soldiers after some careful weeding around the precious crops. However, I’m expecting to see them back on duty this Friday after several days of heavy showers and relatively mild temperatures.

Every day’s a school day, as they say, and my education continued last Friday with an excellent butterfly talk and walk at Pensford Field, led by Ruth from Kew Gardens, who oversees the wildlife in Kew’s Natural Area (formerly the Conservation area). She began by listing the several benefits of butterflies: as pollinators, by spreading pollen from plant to plant while drinking nectar; as part of the food chain in the form of caterpillars which feed wild birds and even wasps; as an indicator species to signal the health of an environment as well as inspiring people to take an interest in the natural world. There’s a huge amount to learn about these fascinating creatures. For example that butterflies detect smell through their antennae which means that in polluted areas their numbers can be reduced because it’s harder for them to detect sources of food. It’s a blessing that places like Pensford Field and the surrounding gardens exist to support butterfly and moth populations, given the proximity of the Field to the South Circular Road.

Other key facts that Ruth shared with us: purple flowers attract butterflies; grow nasturtiums near brassicas as a sacrificial plant to prevent large and small white butterflies from feeding on the crop; stinging nettles are a vital food source for tortoiseshell caterpillars; always site a wilder area of the garden in a sunny spot; treat brambles as a beneficial plant because they provide shelter when other habitats are not available, perhaps during droughts; when you see two butterflies ‘dancing’ in the air, they might be mating or two males fighting! Species with darker wings such as the ringlet which has charcoal coloured wings are more tolerant of shade and can be found in woodland.

Ruth’s talk coincided with the Big Butterfly Count which runs until this Sunday 6 August. I sat in the sun in my garden at the weekend and spied a day flying moth (the Jersey tiger), a holly blue and what I think was a large white.

Although I did no gardening whilst my niece and three great nephews stayed last week, we did spend time in the garden when the weather improved mid week and I introduced the two older boys (aged 7 and 9) to ‘sun printing’. Earlier this year I attended a day course on cyanotype printing at London’s City Lit in March which I reported upon in a blog post. We collected some fallen leaves during a visit to Kew Gardens earlier in their visit and I had been collecting and drying some flowers and fern fronds for a few months in anticipation of their visit. The boys enjoyed the whole process starts with treating the paper with the light sensitive chemicals, drying it the paper with the hairdrier then carefully placing their finds onto the paper. They got really excited when they saw the change in colour of the background of the images once they were exposed to the sun. We dried the washed images on the clothes line and all agreed they weren’t bad for beginners!

Kew Gardens, 3 August 2023

The Shearing of the Green

The season started with weeding an artificial lawn and has ended with a variety of lawn maintenance jobs. I was focussed on mowers and grass when I drafted this post while staying with my niece (otherwise known as my client in the country) as I had offered to cut the lawn of her largeish, squareish, south-facing Somerset garden. In fact, a combination of rain, dew and lack of time meant that I left without mowing the grass for her. Most of my jobs have involved lawn work in the last couple of weeks and I’ve also seen a couple of impressively pristine lawns, both with royal connections.

But before we get to pristine, let’s take a look at the other end of the greensward spectrum. With my Osterley volunteering colleague Andrea Blackie (ablackiegardendesign.co.uk) I carried out a thorough tidy-up of a large garden in Twickenham belonging to INS, a fantastic local charity which provides support for people with neurological conditions such as multiple sclerosis (MS), Parkinson’s disease (PD), and Stroke. The garden is usually maintained by a team of volunteers but like so many places the volunteering programme had to be suspended earlier this year because of Covid 19 and the garden had become rather overgrown. We weeded paths and raised beds and rationalised a number of containers whose contents had gone over. In the absence of a scythe , or a Ross Poldark lookalike to wield it, we used hand shears to cut back the tall grasses established across the L-shaped lawn and raked off the cut stalks and thatch. Then we shuffled our way across the plot on kneelers, removing as many of the coarse-leaved dandelions and low-crowned plantains as we could. Only then did Andrea run the electric mower over for an initial rough cut. With perfect timing, a tremendous thunderstorm crashed across TW2 within half an hour of our packing up for the day, and after steadyish rain for much of the following morning, when we returned 36 hours later for day two of the clear-up, the lawn had perked up and looked more green than brown. Andrea lowered the blades of the mower and cut the lawn once more and I followed with an application of Safelawn, which combines seed and feed, to repair the impoverished grass.

Before
After

On a subsequent visit we would like to scarify the lawn even more, remove any remaining weeds and give the lawn an autumn feed to put it in good heart for 2021. It’s never going to rival the Centre Court at Wimbledon, but with some further TLC it will make a lush foil for the deep border which runs the length of the garden. This is effectively a linear orchard of mature greengage, pear, apple and cherry trees (varieties unknown sadly) interspersed with shrubs such as Mahonia and underplanted with hellebores and Japanese anemones. The latter is a striking deep pink cultivar, revealed when we cut back a couple of wayward shrub branches.

Anemone japonica: cultivar unkown

It was fun collaborating with another gardener for the tidy-up project, and I was grateful not only for the shared labour and company but also the recommendation of Hebe ‘Mrs Winder’ to place in the concrete planters on either side of the main entrance. Although almost waist high, the actual planting depth of the containers was deceptively shallow and the Hebes should be less hungry than the previous incumbents, a couple of conical bay trees. I sourced the plants from the wholesale nursery near Chobham, North Hill Nurseries. It was my first visit since lockdown and I was glad to be there again impressed as always by the quality of the stock and the wide choice of cultivars available. I am usually very disciplined when I’m there and resist the temptation to deviate from my core list, but I confess that I did treat myself to a plant for the top right hand corner of my garden where I’ve twice failed with Erysimum ‘Bowles Mauve’. I succumbed to Caryopteris x clandonensis ‘Heavenly Blue’ with its fluffy sky blue flowers and dainty light green leaves. It looks very good in this position where it will continue the blue/mauve theme from the nearby honesty (Lunaria annua) and Wisteria.

Another purchase that day was a magnificent Hydrangea arborescens ‘Annabelle’ which I planted in a large terracotta container in another client’s garden a week ago. I also gave the lawn there an autumn treatment, raking out the thatch and aerating (or spiking) it using the fork. I applied grass seed to a couple of bare patches which had developed and here again the rain gods obliged and provided a drenching as I was finishing the job.

I promised you pristine lawns at the beginning of this post. The first is in the centre of the turning circle outside the Elizabeth Gate entrance to Royal Botanic Gardens, Kew. I’ve been monitoring it this spring and summer when running around Kew Green, fascinated by its perfection. Short, weedless, stripey: a textbook fine lawn. I’ve watched two kneeling gardeners excise any hint of a weed and I see from this image taken a few days ago that it has recently been spiked. Even the spacing of the holes is precise.

The turning circle at Elizabeth Gate
Aeration by the book

The next lawn has even stronger links with royalty. This striped sward lies within Windsor Castle which I visited at the end of August in order to see the East Terrace Gardens which have been opened to the public for the first time this year.

Within Windsor Castle

Although these rose gardens interspersed with antique bronze statues were beautifully elegant, I preferred the informality of The Moat Garden, adjacent to the Norman Tower of the castle which is the home of the Constable and Governor of Windsor Castle. A snaking red-tiled path runs alongside a border of interesting perennials leading to a rock garden containing a series of waterfalls. Along the way I was drawn towards Poets’ Corner, tucked to one side and lined with garden-themed quotations. The garden is maintained by volunteers and is open to visitors on August weekends.

The stripe maker

A quirky urn nestles beside the plume poppy Macleaya cordata ‘Flamingo’

Next time I leave lawns behind to visit Homeacres, the realm of the king of No Dig, Charles Dowding.

In the Dock

Last Friday, after an absence of 127 days, I returned to volunteer in the garden at Osterley House. My last session was in early March when we spent the day in the sunshine clearing brambles from the margin of the Middle Lake.

Bramble clearing on 6 March 2020

In the photographs I took that day I see that the rosemary in the borders at the rear of the house was in full bloom, the grey green foliage complementing the clear blue flowers with their prominent lower petals. In the Cutting Garden I photographed the Anemone coronaria ‘St Brigid’s Series’ against a chrome yellow backdrop of daffodils. Little did I know when I took these images it would be four months until I was in the garden again.

Anemone coronaria ‘St Brigid’s Series’
Rosemary

It felt so good to be back, another step nearer normality in the gradual easing of lockdown. Naturally a new normal has had to be established. Flasks of tea brewed at home replace the lunchtime teapot ritual and the tool handles have to be disinfected when we finish for the day. Two of the five volunteers weeded in the Tudor Walled Garden and planted several new additions in one of the potager style beds. One of these plants was Viper’s Bugloss (Echium vulgare). Thankfully its appearance belies the slightly sinister sounding common name, the spires of rosemary blue flowers being a magnet for bees and other pollinators.

The rest of us trimmed the edges of the four rectangular beds in that area, moving via the Magnolia borders to work our way along the paths in Mrs Child’s Flower Garden, our razor sharp shears guided by the metal edging strips to create that crisp finish which instantly neatens a lawn. Head gardener Andy Eddy was mowing the lawns in ‘Mrs Child’s’ and stopped for a catch up. During lockdown he and his partner maintained the garden, enjoying the temporary lull from fewer planes heading to Heathrow and the vastly reduced traffic on the M4 which borders the parkland surrounding the garden. There was also the novelty of the presence of the neighbouring farmer’s Charollais cattle herd on the field immediately in front of the house.

We sat outside the bothy to eat lunch, the reduced number in the team making social distancing easy to achieve. Afterwards we worked in the cutting garden, keeping the bark topped paths clear of weeds and transplanting stray self-seeders such as geraniums into the relevant sections of the garden. I found that the portion of the border beside the wall where I was working was choked with docks (Rumex obtusifolius) and as I worried away at this patch with first a hand fork and then a border fork I realised that I haven’t had to clear these before and had no idea how difficult they are to tackle. To find out more about what I had hitherto assumed were innocuous weeds with the benefit of calming nettle stung skin, I consulted the RHS website which states ‘They are often difficult to eradicate as their deep tap root can regrow from the top section and they produce large amounts of seed.The tap root can be up to 90cm (3ft) in length.‘ A 3ft tap root: no wonder I struggled!

I did manage to clear a section of roughly a couple of feet square but confess that, with the permission of gardener Graham, I had to cut several of the most persistent plants down to ground level rather than rooting them up. It felt appropriate that almost my first task as a ‘re-opening volunteer’ was the clearance of stubborn weeds, just as that last pre-lockdown session had involved bramble eradication. Despite my emphasis in this post on weeds and weeding, the gardens at Osterley are looking stunning as the following photos attest.

The Cutting Garden 10 July 2020: Echinops and Alliums

Robert Adam’s Garden House
Fuchsia Thalia inside the Garden House
Crocosmia and Honey Spurge (Euphorbia mellifera) in the Tudor Walled Garden

Turfing it out

Extracting weeds from an artificial lawn requires a very different technique to that applied to a lawn of real grass. I soon found this out when I tidied a neighbour’s back garden last week. For a start, a hand fork or trowel is unnecessary since the weeds seem to embed themselves into the weave of the material to which the ‘grass’ is attached. No need here for a sharp implement to loosen the soil around the weed’s roots before yanking the weed from the ground. Instead, the weed needs to be grasped between thumb and forefinger and gradually pulled up with a final gentle twist to keep the roots intact. I have never seen roots so clean! I was surprised to see that even an artificial lawn can host weeds but the weeds I removed were ephemeral weeds like groundsel (Senecio vulgaris) and hairy bittercress (Cardamina hirsuta). No ‘lawn spoiler’* to worry about here like greater plantain (Plantago major) . And I suppose that is the merit of an artificial lawn: even if some enterprising little weeds manage to embed themselves into the surface of the material, the long-rooted perennial weeds cannot penetrate the thick polypropylene base.

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This was my first experience of working with synthetic grass and although I’m by no means a convert, I can see that compared to a real lawn there is no need for cutting, edging and feeding. This lawn looked particularly authentic and included material which seemed to mimic the straw-coloured thatch that accumulates at the base of grass stems over time. In a real lawn this has to be raked out from time to time to make room for fresh blades of grass to grow.

As I carefully removed the weeds I began reflecting on the growing popularity of artificial grass and not only in domestic gardens. A mile and a half from here, were it not for the Coronavirus crisis, the newly built stadium to be shared between Brentford FC and London Irish RFC would soon have opened its doors for the first time. We hope it will still open in time for the new season in the summer.  Having read somewhere that many modern football pitches are created using a hybrid of real and synthetic grass, I determined to find out more. I approached Nity Raj, a parkrun friend and director of Brentford FC, to ask him about the system used at the club’s current ground, the dearly loved Griffin Park, and at the new Brentford Stadium at Kew Bridge. Little did I know as we chatted on Saturday mornings over peppermint tea after the weekly 5k run at Richmond’s Old Deer Park, that Nity knew anything about this topic. Here he generously shares what he knows about football pitch technology:

The current pitch at Griffin Park is a stabilised natural grass pitch.  The stabilised element comes from a plastic weave which was woven into the turf before the grass was grown and the turf was cut and relaid at Griffin Park.  It looks a bit like a tennis net, but with smaller squares.  The plastic matrix significantly reduces the amount that the surface is broken up during play making the regular pitch works much easier to manage and  repair of damage more effective.  We haven’t always had this kind of stabilised pitch.  Until the summer of 2015 the pitch was a normal seeded grass pitch.  We worked with specialists to re-lay new drainage and an entirely new pitch, incorporating the plastic matrix.  Since then I am told we have had the best pitch we have ever had in our history, with significantly less damage visible, especially during bad weather periods, when previously the pitch was prone to getting very badly damaged especially in the high traffic areas of the pitch. 

In the new stadium we are installing a Desso Grassmaster pitch.  Desso are the leading pitch tech company and their pitches are used in many of the most prestigious football and rugby stadiums in the world..  Desso have a different system from the one used at Griffin Park in that it involves a machine injecting fibres into the ground.  We believe this kind of system will best suit the pitch being used for football and rugby.

It’s worth saying that the pitch at Griffin Park and the pitch at the new stadium are both virtually indistinguishable from ordinary grass pitches.  The pitches look, play and smell exactly like grass pitches except for their ability to rejuvenate and resist damage.  Without careful management by our excellent groundsmen, they would also be susceptible to weeds, just like any wholly natural grass surface

The list of venues in the Grassmaster Wikipedia entry reads like a roll-call of world-famous soccer and rugby grounds and includes Wembley, Twickenham, Old Trafford, Parc des Princes, the Emirates Stadium and Anfield. And it will soon be joined by Brentford Stadium.

The hybrid pitches installed for playing professional football and rugby are a far cry from the artificial lawns which are becoming increasingly popular in domestic gardens where the lawn is laid rather like a carpet. Indeed, I’m told that some householders have been known to vacuum their Astroturf! I’ve already mentioned that there is no use for trowels or forks when weeding artificial turf. Nor for a rake as I discovered last week when I initially tried to clear away an accumulation of dried bamboo cane sheaths and leaves. I soon found that a stiff bristled brush is the ideal tool for this purpose. I confess that seeing a green expanse entirely devoid of weeds after a few hours’ gardening was surprisingly satisfying.

Am I now a convert to the pseudo sward? The answer is no, because for all its benefits- neatness, hygiene, consistency- this inert material lacks two of the essential elements of real grass. The coolness under bare feet of grass on a hot day cannot be replicated, nor can the scent of newly mown grass. In the last day or so I have detected that distinctive smell drifting across from neighbouring gardens where the instruction to stay home has prompted many householders to cut their lawns for the first time this year. And to Dig for Victory and grow vegetables, but that’s another story and one I shall address in a future blog.

*William Edmonds ‘Weeds Weeding (&Darwin)’ ISBN-10: 0711233659

 

Clean, Calm and Camellia

Camellia oil? It sounds like a luxurious product I should be applying to my face after a hard day’s gardening. But it’s my precious hand tools which will benefit from a treatment with Niwaki’s Camellia Oil. Made with oil from the cold-pressed seeds of Camellia oleifera, it is a traditional Japanese method to protect tools from rust.

I first heard about Niwaki when Jake Hobson addressed the Kew Mutual Improvement Society in December 2017 on ‘The Art of Creative Pruning’. Jake’s artistic approach to shaping shrubs reflects his origins as a sculptor, and his work combines both Japanese influences and traditional topiary techniques. I recall inspiring images of the extraordinary topiary garden at Levens Hall in Cumbria and cloud-pruning both here and in Japan. In addition to his creative pruning activities, Jake Hobson co-founded Niwaki which supplies Japanese garden and kitchen equipment with an emphasis on cutting tools and accessories. When I started Weeds Roots & Leaves 18 months ago I invested in a pair of the company’s hedging shears which are light, very sharp and are supplied in a substantial leather holster. They have been invaluable when shaping and maintaining large yew and Cotoneaster dammeri specimens in two of my client’s gardens.

I chatted to a company representative on the Niwaki stand at last week’s Garden Press Event at the Business Design Centre in Islington. I asked if I could hold and weigh in my hand the Hori Hori, which translates from Japanese as ‘dig dig’. This narrow, asymmetrically bladed trowel is very versatile and I can see how useful it must be for tackling long rooted weeds (I’m thinking bindweed, both ‘hedge’ and ‘field’) as well as for planting bulbs.

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The Hori Hori

The tool was on sale at the shop located next to the exit of the sculptor Antony Gormley’s exhibition at The Royal Academy last autumn. It somehow didn’t feel incongruous to see this elegantly designed garden tool displayed in such a venue, particularly in conjunction with a show where many of the exhibits were executed in steel. After all, designer William Morris famously wrote ‘If you want a golden rule that will fit everything, this is it: Have nothing in your houses that you do not know to be useful or believe to be beautiful.’

At the event last week, as well as the Hori Hori, I admired some rather more expensive implements which were hand-forged, the blacksmith’s hammer marks being clearly visible on the intriguingly shaped Japanese trowel and axe. As I left the stand I was given a ‘Crean Mate eraser’ with which to clean rust and sap from my hand tools. I tried it the other day on my secateurs and as the images show it is very effective. The gently abrasive block can be dipped in water or Camellia oil before being rubbed across the area to be cleaned. I used water but have now bought a 100ml bottle of the oil with which to protect the secateurs (and the shears mentioned above) in between gardening sessions.

In my recent blogs I’ve commented on how mild the weather has been this winter and I can see that the buds on the camellias currently in flower in local front gardens and along Camellia Walk in Kew Gardens are undamaged by frost. They have unfurled into perfect blooms, without the browned petal edges which can occur in severe winters when the buds are subjected to very cold conditions.

I included the word ‘calm’ in the heading to this blog not only for alliteration (and a rather laboured pun on the title of Culture Club’s hit single in 1983), but because the good old cuppa is made from the leaves of another species of camellia, C. sinensis. Amidst the current uncertainties, when a cup of ‘Rosie Lee’ helps us to keep calm and carry on, it’s comforting to know that the cup that cheers is another product of this useful and beautiful genus of plants.

The Generous Garden(er)

‘I describe it as a generous garden’, my new client explained earlier this year when showing me around her garden before engaging me to assist with seasonal maintenance tasks as and when needed. The long slim plot behind a Victorian terraced cottage was brimful of treasures when I first saw it at the beginning of May and vegetation was thrusting out of every available inch of soil. At every turn along the narrow lawn between deep curved edge borders I spied interesting plants- to one side a statuesque tree peony and the Euonymus alatus or Spindle Tree. And on the other side: large stands of Veronicastrum virginicum ‘Fascination’ and Acanthus mollis (Bear’s Breeches). The overall effect was punctuated by light purple dabs of Honesty flowers (Lunaria annua).

A keen and knowledgeable gardener, my client has loving maintained this extraordinarily productive space for more than three decades. She attributes its ‘generosity’ to regular and liberal applications of well-rotted manure and garden compost. These have contributed to a deep layer of humus rich soil, teeming with earthworms. An open aspect, unimpeded by mature trees in neighbouring gardens, and an irrigation system snaking across all the borders, also play their part. Unlike more recently planted gardens where the black irrigation pipes can look quite unsightly lying on the surface of the soil, these pipes are hidden amidst the undergrowth.

Inevitably uninvited guests presume on the garden’s generous hospitality. One morning last week I removed at least a dozen substantial plants of Green Alkanet (Pentaglossis sempervirens), those Borage relatives which masquerade so convincingly as Foxgloves until the last minute when their forget-me not blue flowers emerge. By this stage their deep roots have secured a toehold at least six inches beneath the ground, rendering them tricky to extricate from surrounding growth without snapping. Like Dandelion removal, it is all the more satisfying when the root emerges intact. Fortunately the recent rains and a fundamentally sandy soil mean that in this garden this is a relatively easy task.

More welcome guests I have seen whilst working in this garden are robins and blackbirds and last week a vividly green-plumaged Rose-ringed Parakeet roosted for several minutes on a branch a few metres from where I was working.

During one of my May visits one job was to tidy the three chunky clumps of Liriope muscari near the rear of the garden. I stripped away last year’s browning leaves from the healthy dark green strappy leaves into which they were embedded. It was a joy to discover that the garden had repaid my earlier efforts with a stunning display of bright purple flower spikes, a sumptuous foil for the orange, yellow and scarlet flowers of the hugely overgrown and soon to be grubbed up Nasturtiums which had escaped from a neighbouring bed and overrun the sunny paved area at the rear of the site.

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Liriope muscari

Beyond this paving is a deep border backed by a brick wall which I cleared of spent tomato and runner bean plants, as well as several suckers of the Stag’s Horn Sumach (Rhus typhina). My client tells me this spectacular tree was itself a blow-in from a nearby garden. The same border also houses a fair sized peach tree which is ideally placed in its due south-facing location.

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Golden dahlias in the foreground of the Stag’s Horn Sumach in its autumn glory

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The client often sends me home with a bunch of beautiful Dahlias

In another client’s garden, that adjective ‘generous’ crops up again, this time applied to a David Austin climbing rose which I recently pruned and then trained against the fence, having first installed three rows of strainer wire. ‘The Generous Gardener’ (the definite article is part of the name) is described in David Austin’s catalogue as ‘a rose of delicate charm with beautifully formed flowers…a soft glowing pink at the centre, shading to palest pink on the outer petals…when open, the numerous stamens create an almost waterlily-like effect’. Judging by the girth of some of its lower stems this rose was planted many years ago and had, as often happens, grown into the habit of reaching skywards with few flowers below a height of a couple of metres. The time had come to fan out the stems against the fence, and by encouraging them in a near horizontal direction, to produce flowers as far down to the base of the plant as possible.

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Generous she may be but in her mature years this rose has developed some serious thorns and both pruning and training proved challenging. But now that I have started the taming process, I am optimistic that next summer the promised perfume of ‘Old Rose, musk and myrrh’ will fill the courtyard garden rather than evaporating into the branches of the neighbouring garden’s trees. Some yers ago I gave this rose to a friend as a present and earlier this year helped her to support it with a hastily lashed together trellis of bamboo canes. I anticipate this proved a flimsy solution and have made a mental note to ask after The Generous Gardener and check that the extravagant horticulturist of the rose world has not exceeded her brief and attempted a takeover of my friend’s garden.

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Oh no, knot another weed!

In the 80’s, 90’s and noughties, when the author’s life was more ‘Reads Books & Deeds’ than ‘Weeds Roots & Leaves’, the nearest a property lawyer came to horticulture when acting in the purchase of a house, was to enquire of the seller’s solicitors if that large tree in the garden was the subject of a Tree Preservation Order. Since 2013 it is standard practice for the seller of a property to declare whether  Japanese Knotweed*, Fallopia japonica, is present on the property in the Property Information Form. This means that it is the seller’s responsibility to check the garden for this invasive weed and if it is present to provide a management plan from a professional eradication company. Once a buyer’s solicitor has noted the presence of the weed when checking the form, and has notified the lender, the latter is likely to seek assurance that it will be eradicated, in the form of a management plan, before agreeing to fund the transition. Failure to disclose the presence of Japanese Knotweed or the lack of a management plan will delay the sale and increase the cost of the buying process or, the worst case scenario, give rise to a potential misrepresentation claim.

How has a plant introduced from the Far East in 1825 as a garden ornamental, and praised by innovative William Robinson in 1879 as ‘one of the finest herbaceous plants in cultivation’, developed a reputation as a possible property deal-breaker? Had Japanese Knotweed confined itself to the garden, the story would have ended here, but it escaped from gardens to establish colonies beside railway lines, waterways, roadsides and on waste land. By shielding lower growing species from light with its dense canopy it obliterates local native vegetation and its fallen leaves form a dense mulch to suppress the growth of any incipient seedlings. In the UK it spreads not by seed but by a huge rhizome system, impervious to many herbicides and needing a saw to sever the rhizomes. I can understand why our gardening forebears liked this plant- it has an attractive and exotic appearance with up to 2 metre tall bamboo-like stems speckled purple, heart shaped leaves about 15cm long and sprays of small white flowers. It would fill a shady corner very satisfactorily were it not for its thuggish tendencies.

As well as competing with native species, it contributes to river bank erosion and increases the risk of flooding. In a residential or commercial property context, it can cause structural damage by forcing itself through paving and concrete foundations. Indeed under the Environmental Protection Act 1990 Japanese Knotweed is classified as controlled waste. This means that a property owner must prevent it from spreading into the wild and causing ecological damage. If it discovered on a property it does not have to be removed but the property owner can be prosecuted for allowing it to spread onto someone else’s property and will understandably wish to find a satisfactory means of control. The bad news is that such means are both drastic and expensive. A few examples follow:

  • Spraying, over a course of at least three years, with chemicals that are approved herbicides, until the underground rhizomes become dormant.
  • Burying the waste at a depth of at least five metres (!), having first sought the approval of the Environment Agency.
  • Arranging for the waste to be carried off-site by a registered waste carrier to be taken to an authorised landfill site.

Needless to say,  bio-security precautions are essential when dealing with this species and tools, boots and gloves require thorough cleaning and disinfecting after handling Japanese Knotweed to prevent pieces of plant material escaping and forming a new problem-laden clump. One recommendation I have read for how to deal with Japanese Knotweed is to move house! In light of the issues I have mentioned during the conveyancing process this may be easier said than done.

Before I move onto a more positive member of the knotweed family, I have seen the damage that an invasive plant can do to a building. In this case not Japanese Knotweed but the Tree of Heaven, Ailanthus altissima, whose roots had penetrated the foundations of a local church at the point where the wall of the building met the neighbouring path. I saw the plant material growing between the floor tiles inside the church! The tree, which was beautiful but unsuitable for planting so close to a building, has now been removed, but only after a protracted negotiation with the local authority.

Japanese Knotweed is a member of the knotweed family, Polygonaceae, which also contains the genus Persicaria. I planted a species of this plant in my garden earlier this year and I believe it is Persicaria amplexicaulis, or red bistort, I rescued it (with permission) from the ‘muddy clumps’ heap near the gardeners’ bothy at Osterley, a sort of holding area where discarded plant material is put before the garden team decide whether to compost it or use it for propagation. Although it did not flower until September, it put on a lot of vegetative growth during the summer, and has withstood a couple of overnight frosts and is still going strong this first week of November. The Royal Horticultural Society describe the plant as a robust, clump-forming, semi-evergreen perennial. All good qualities but I anticipate it might one day grow too large for this small garden. In the meantime I shall enjoy its narrow spires of reddish pink flowers atop a crown of pointed mid green leaves measuring 25cm with a slightly puckered appearance.

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The hard to photograph Persicaria

I am charmed by the idea that Persicaria hails from the Himalayas and can imagine it forming an understorey for Rhododendrons and Camellias on the mountains’ lower slopes. Quite a leap to a suburban garden, but the same can be said for many of our now familiar garden plants which originated thousands of miles away. And it reassuring to know that not all the plants under the knotweed ‘umbrella’ create a headache for the conveyancer.

  • Useful information about Japanese Knotweed and how to control it and dispose of it can be found at gov.uk and at RHS

 

Such a bind: two foes and a friend

Having spent many of my hours in the garden this summer waging war against an invading army of the twining stems of Hedge Bindweed, Calystegia sepium, I found myself pondering whether other members of the Convolvulaceae family might have more merit in a garden context. A recent day in the Tudor Walled Garden at Osterley House and Garden provided the answer: yes and no!

Although its white trumpet shaped flower is attractive, it is better to prevent Hedge Bindweed flowering in the first place so as to avoid the plant setting and scattering seed. A pernicious perennial weed, it also spreads via a prodigious root system which can colonise mixed borders and, if left unchecked, strangle the plants it scrambles up and around. Where this is allowed to happen, the plant beneath is all but obliterated by a cloak of overlapping heart shaped leaves with prominent drip tips.

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Calystegia sepia on the banks of the River Crane in Twickenham

I’ve always tried to control this unwelcome tenant in the flower bed to the left of my own garden by removing it by hand, carefully prising the roots from the soil and taking care not to snap off the white fleshy root before extracting its tip. This is easier said than done and I’ve learnt that the roots extend for several metres like an underground rail network with numerous branch lines. When the bed is filled in the growing season with herbaceous specimens, it is impossible to remove the Hedge Bindweed completely and it is just a question of being vigilant and removing it as soon as it emerges. When the plants in the bed have died back in the winter months is the time to dig out as much of this root system as possible.

This summer, for the first time ever, I became so frustrated by this wretched weed penetrating from the neighbouring garden beneath the gravel board at the base of the fence and entwining itself  around every plant in this bed, that I resorted to using a chemical control in the form of a herbicide gel. Applying Glyphosate gel to the leaves of the weed is a tricky task because it is imperative to avoid the foliage of other plants. The gel took effect within a few weeks with the treated stems turning brown and the leaves withering. However, in the meantime, a report about the potentially carcinogenic impact of the chemical was widely publicised and my brief flirtation with non-organic gardening came to an abrupt end. When the bindweed was at its worst I nursed a megalomaniac’s fantasy of replacing the fence with a wall with footings deep enough to stop the onslaught, but the thought of the disruption and expense soon put pay to that.

Field Bindweed, Convolvulus arvensis, is another unwelcome member of the bindweed family. It is singled out for special attention when weeding the four large ornamental vegetable beds which make up Osterley’s Tudor Walled Garden. With smaller leaves than is cousin from the hedgerows, its flowers are smaller and pale pink. Its habit is to creep along the soil, supported by another immense root system. I’ve read in a wonderful book, ‘Weeds Weeding and Darwin’ by William Edmonds, that the roots can descend as far as five metres. Like Hedge Bindweed, the upper roots are brittle and because the weed will regenerate from any fragments left in the soil, one of the cohort of garden volunteers is appointed to concentrate on Field Bindweed removal and to extract as much of the root as possible collecting the debris in a separate bucket from those used for other less pernicious weeds. This material is not tipped onto the heap waiting to be composted but is placed in a separate container in which to rot down, lest it contaminate the compost carefully created by the Osterley garden team for use as a mulch throughout the garden in early spring.

It was while working in this spectacular section of the gardens at Osterley a fortnight ago, in a bed where cucumbers and courgettes grow alongside lime green Nicotiana and white spider flowers, Cleome spinosa, that I encountered, trained up an obelisk, the benign and very handsome  Ipomaea purpurea ‘Grandpa Ott’. This is a cultivar of Morning Glory, an annual cousin of the unwelcome bindweeds mentioned above. Osterley’s Head Gardener observed that unlike the plant bearing the clear blue flowers of the classic Morning Glory, ‘Grandpa Ott’ does not succumb to powdery mildew. Its deep purple flowers are velvety and prolific. I was assigned the task of gathering the black peppercorn like seeds into an envelope and a few minutes of popping open the fragile dried seedheads yielded a substantial harvest, ready to sow for next year’s display. I am happy to have observed that not all members of the bindweed family are a bind.