Stay at home and tour the world: Part 2 South and North America
Welcome back to Weeds Roots & Leaves’ global garden tours. Today we’re visiting the Americas: south, central and north. There has been some debate at tour HQ (interesting how a pandemic amplifies one’s internal dialogue!) about whether North and South America are classed as one continent or two. Whilst researching this point I have read that before the Second World War the USA viewed them as a single continent, but now geographers worldwide treat them as separate continents. When I calculated the total number of continents visited on this tour (five) I adopted the latter approach.
Had this tour been real rather than virtual we would at this stage have embarked from the shores of New Zealand to cross the Pacific. The nearest body of water I can muster is a small pond. A few days ago rustling sounds emanating from the dense thicket of hard rush (Juncus inflexus) at one end of the pond and a faint series of croaks hinted at the return of amphibian life to the garden. On Easter Sunday I saw two frogs luxuriating in the cool water and the warmth of the spring sunshine. Once this dry spell of weather comes to an end they will no doubt have an endless supply of snails and slugs on which to predate.
We find the first two plants from the New World in Brazil. I first saw bog sage (Salvia uligonosa) in the gardens of the Palace of Versailles on a visit last August. It was the unusual shade of blue that attracted me: light but not insipid. Fringing parterres near the palace, their height (1.5m to 2m) and profusion of flowers made an impact. Last October one of the gardeners at Osterley gave me a portion of a plant which had recently been divided telling me it was quite tender and would need to be under cover in the winter. I have been checking the specimen regularly and until this weekend it would have been an exaggeration to say it was thriving but this weekend I was relieved to find a couple of fresh stems emerging at its base. Once the threat of frost has passed at the end of April I shall plant it in a sunny spot next to its close relatives, natives of the next country on the itinerary, Mexico, in what I have decided to call the ‘Salvia Bed’, in homage to Kew’s splendid Salvia Border.
I cannot leave Brazil without taking a look at Verbena bonariensis. This too I first saw at a grand palace: Blenheim in Oxfordshire. It was probably 20 years ago and at that time these tall slender stems topped by purple flowered ‘cymes’* swaying above lower growing species were an unusual sight. Since then this has become a very popular choice for providing height without bulk in a planting scheme. It is elegant, takes up little room at its base and is easy to grow. Its geographical range is from Brazil to Argentina: indeed its alternative species epithet is V. patagonica. Although it self-seeds quite freely, I’ve always found it does so in appropriate places. Flowering from mid-summer to early autumn, it has to be one of the hardest working herbaceous perennials in the garden. Furthermore the seedheads can be left untrimmed over winter for structure and interest.
Leaving South America, our route leads us beyond Central America to the North American continent, first stop Mexico. There are three Mexican plants in this section of the tour, all introduced to my garden from the gardens at Osterley. Yesterday I planted the sage relative, pakaha or pitcher sage (Lepechinia hastata), in the Sage Bed after a winter’s protection in the upright cold-frame next to the kitchen window. Were I to adopt airs and graces I could call this a mini greenhouse, but in my opinion to qualify as a greenhouse it must be possible to open the door and step inside. Until I can find a way to miraculously expand the garden to accomodate such a structure, this two shelf solution is wonderfully useful: more later. A mature specimen of this sub-shrub can grow to 1.5m bearing spikes of tubular purple-magenta flowers in late summer. Its felty grey-green leaves are spear-shaped, or ‘hastate’, from the Latin ‘hasta’, meaning a spear. When rubbed, the leaves have an intense fragrance, like a rich blend of essential oils. Judging by the number of stock photographs featuring visiting bees, the flowers will be attractive to pollinators.
I recently planted up a Dahlia tuber into a container but have no idea what colour its flowers will be. It came from last year’s scheme in one of the potager style beds in Osterley’s Tudor Walled Garden which means it could be a deep wine red, vivid scarlet or the very pale pinky beige shade the fashion pages refer to as ‘nude’. A good place to see a spectacular Dahlia display in late summer is in the asymmetric walled garden at Kelmarsh Hall in Northants. Let’s hope the current crisis will have eased by August and September when I anticipate there’ll be a frenzy of garden visiting. In the meantime we shall have to settle for virtual tours such as this.
I’ve no wish to mimic one of those tour operators promoting hotels which on arrival turn out to be half built, so I confess here that the next Mexican plant has yet to germinate. I sowed the flat papery seeds of the cup and saucer plant (Cobaea scandens) approximately a fortnight ago, having harvested them from a fruit of one of the specimens trained up the hazel pole pergola which is the centrepiece of the quadrant of beds in the Tudor Walled Garden at Osterley. I had left the fruit on the kitchen windowsill for months, fearing it might go mushy and mouldy, but it dried perfectly and when opened, revealed dozens of seeds neatly stacked inside its four chambers. I understand the seeds need bottom heat to germinate and fear they may not reach the requisite temperature. But it’s too soon to give up and I would be thrilled to grow one of these vigorous climbers from seed. The large flowers can be cream or mauve and do indeed resemble a cup resting on a saucer. A prolific example of the plant grows at the base of the down spiral staircase in the central section of Kew’s Temperate House (diagonally opposite the Tree Ferns). While clearly at home in that protected environment, at Osterley it flowers well into a cool and rainy autumn, until finally seen off by a frost.
Following the spine of mountains northwards from the Sierra Madre to the Rockies, leads us to the home of that versatile ground cover plant, Heuchera. Coming from rocky woodland sites, in my garden it thrives in the ‘Woodland Area’ and alongside Cyclamen hederifolium in a large terracotta pot beside the garden gate. The beauty of Heucheras lies chiefly in their foliage, with wide variations in leaf margins and colour. Leaves range from deep mahogany (H. ‘Palace Purple’), through a lime green cultivar to my favourite, the roundly lobed leaves of which are shaded apple green fading towards the centre to a silvery white, intersected with burgundy veining. I touch wood as I write this, but I have not known these specimens to suffer vine weevil larval damage, a common problem for this group of plants causing the entire upper structure to part company with the roots when the pest has munched through the stem.
I grow another North American ground cover plant, Tellima grandiflora, which comes from cool moist woodland from Alaska to California. Like Heuchera it grows in a low rosette and carries its flowers above the plant on slim stems.
Before leaving the Americas, I should mention that I have joined the dig for victory brigade and am growing two crops introduced to Europe from the New World. Tomatoes (Solanum lycopersicum) and potatoes (Solanum tuberosum), both members of the nightshade family. The tomato seedlings are doing well in the tall cold frame having sprouted their first non-seed leaves and I’m growing the potato variety ‘Charlotte’. I’m experimenting with new kinds of container for both crops and shall explain more in a future post.
In my small garden alone it’s been striking while planning this itinerary to discover how many of the plants in my garden come from Asia or the Americas. But the time has come to travel east across the Atlantic to Europe. And I haven’t forgotten the promised side trip to Africa. I look forward to welcoming you to the third and final part of the tour.
*As in Part 1 of the tour I thought it would be helpful to include a drawing showing some differing flower forms.