Finding hidden treasure

Press, 15 October 1982, Page 14

Finding hidden treasure

Gardener’s W DIARY

Derrick Rooney

By no means the least interesting thing about plants is that they are full of surprises. The most common, or the weediest, family is capable of concealing a treasure.

Last week I wrote about some of the treasures hidden among the linarias. I might just as easily have written about foxgloves, or the Californian poppy that brightens our riverbeds in summer. The latter, which comes wild in shades of orange, must be one of the toughest naturalised plants; where it occurs, in riverbeds and stony soils, it always seeks out the hardest and hottest sites and it grows just as vigorously and flowers just as prolifically in seemingly barren gravel as it does if brought into fat garden soil. It is reminiscent of the dandelion, in that if it were something rare and difficult from the heights of, say Californian Sierra; the would become one of our most precious possessions. Of course, the Californian P O PPy genus does include at least one plant which is rare, and which is at least as difficult to grow as its name is to spell. This is Eschscholzia caespitosa, a little wisp of a thing with a miniature, bluegreen version of the usual finely divided Californian poppy foliage.

In summer it bursts out in small, perfect poppy flowers in a scrummy shade of cool yellow.

It is on annual. Sedlings coipe up in spring if the site suits it, but it is easy to lose because it is in the habit of collapsing overnight if something, anything, is not to its liking, and it. cannot abide being overgrown — a common characteristic of plants from semi-arid areas. Then there are the foxgloves. The common foxglove, Digitalis purpurea, is a naturalisised weed in many districts, but there are other species which are not so easy.

Digitalis orientalis is one that many collectors yearn after. It comes from" Asia Minor, so called, and is quite small, only 40cm high; it has spikes of flowers fluctuating between buff and orange, with pouting lower lips outlined in white.

According to descriptions of it in habitat it is a rupestral species (i.e. it grows among rock outcrops) so it presumably likes sharp drainage and free movement of air around it. Unfortunately, I haven't yet had an opportunity to find out. I have not grown this species, and I doubt if it is obtainable here at present.

Several times I have sown seed or bought plants advertised as Digitalis orientialis, but all have turned out to be forms of the European D. ferruginea, which is an admirable plant but is not in the class of D. orientalis and is far too tall for the rock garden because it can grow as high as an adult human. In the border. Digitalis ferruginea is not to be sneezed at. Its tall spikes of flowers are intriguing. Each bloom is rusty orange-brown, with a long lower lip, very hairy, and a barrel chest like a pouter pigeon. Unopened buds have a curiously bulbous appearance, like whales turned upside down. Officially, the plant is a biennial, growing one season and flowering the next, before seeding and dying, but if it is prevented from seeding it lives several years, gradually weakening and eventually just fading away. I haven't planted this foxglove for several years, but there is always a seedling or two somewhere in tlje garden. and I leave them to get on with their own busieness.

The ordinary Digitalis purpurea, keeps turning up in the garden also, though I haven’t knowingly planted it. Most of the seedlings originated, I think, from a plant that came, under a fancy name, some years ago from a North Island mailorder nursery. Digitalis thlaspi, I think it was labelled: it turned out to be

just a slightly pinkish form of the commom foxglove. There isn’t anything wrong with the common foxglove — I always have a plant or two somewhere. But I don’t want any extras, thank you. In England gardeners can buy “improved” strains with extra-tall spikes beset on all sides with large flowers in a range of colours including many pink and pastel shades, but we are not permitted to have then here.

However, a New Plymouth seed firm now offers a strain called “Foxy” which sounds very much like a form I grew for several years, so I have ordered a packet. This form was Digitalis purpurea var. gloxinioides. which grows shorter than the ordinary type and has rather larger flowers. At the top of each spike sits a solitary, enormous, upward-facing flower. These plants were also nominally biennial but some of them lasted for four summers. A hybrid of the common foxglove with the Grecian

species. Digitalis grandiflora (formerly ambigua). is sometimes offered in nurseries under the name "Digitalis mertonensis."

Grandiflora has yellow flowers, and the 'cross appears in several shades, but the one usually offered is a crushed strawberry colour. A short-lived perennial, it must be divided regularly and moved on to fresh soil if it is to survive. As its name indicates. it was raised at the John Inness Horticultural Institute at Merton. Surrey. A number of wild species of foxglove have yellow flowers. One. which I grew, several years ago. had a mixture of yellow and pink, with a longer lower lip than the common foxglove and only a slightly bulging midriff. The flowers drooped gracefully on the spikes. Chief among the glories of this plant were its leaves, which were intensely whitefelted. more like mullein leaves than foxgioves. The plants looked as if they should be perennial, but were either not very hardy or

disliked our humid winters, and they did not last.verylong. They resented being transplanted — unlike the common foxglove, which can be moved in full, flower without turning a hair.

All of them made strong growth in the first season, and flowered splendidly, but then dwindled away, leaving no seedlings. They did not divide. I still look hopefully at every grey-leaved seedling that appears in the garden, but none has been the precious. nameless foxglove.

A foxglove which has kept going for four or five years is the charming oddity. Digitalis obscura, from Spain. This looks more like a penstemon than a foxglove (both belong to the figwort family, Scrophulariaceae. as also do the New Zealand hebes).

The stem is hard and woody, and the leaves are very narrow, smooth, and long. The flowers are like little penstemons. with tubby lips and a moustache underneath. They are rusty brown spotted with orange, or orange spotted with rusty brown. I'm not sure which. My original plants are now four or five years old. and some of them are beginning to look geriatric. I keep searching for seedlings but none have apppeared yet in the garden, though I do have a panful of tinies from a pinch of seed that I and sowed saved, in a pot last year. This is the only way to propagate Digitalis obscura — because of its woodiness it cannot be divided, and cuttings will not root. Digitalis obscura grows - about knee high and is useful for nooks where visitors can chance across it when they think the garden has already yielded up all its surprises. Maybe that’s why it is call “obscura." It is the only truly perennial foxglove that 1 have grown. Another which is showing strong perennial tendencies is a little plant that I got from seed lablled “Digitalis, species pink." This has smooth leaves like a little ferrugined and is forming a’ dense tuffet. It flowered last summer, but I can’t for the life of me recall what the ' flowers looked like. If it doesn’t make a stronger impression this' season it may have to go. I have only the one plant, which is odd because foxglove seeds usually come up ' like mustard and cress.