Jane Powers delves into the shady undergrowth to find some secret constellations of colour
Now is the time of year for one of the most magical of plant groups, the dainty woodlanders. Fallen constellations of luminous wood anemones spangle the ground, mists of bluebells shimmer through the undergrowth, and pale surprises of primroses brighten the shady sides of banks and ditches.
These plants are all natives, and may be found growing in a quiet corner of the country somewhere not too far from you - so do seek them out for a spot of communing, before their season is over.
Yet there are shade-lovers from all over the world that will grow happily in our Irish gardens - adding a little extra light to the start of the gardening year. Many of our best-known spring flowers come from the treasure-rich belt that stretches from southern Europe across to Japan and China. Among them are several hellebores, false forget-me-not (Brunnera macrophylla), bleeding heart or Dutchman's breeches (Dicentra spectabilis), and some spurges (Euphorbia) - which I wrote about last week. As I mentioned, the best of these for dry shade is Mrs Robb's bonnet (Euphorbia amygdaloides var. robbiae) - but let me remind you again that it has strongly invasive tendencies, so don't let it loose anywhere other than the most difficult-to-colonise parts of your garden.
Also from this long and broad strip of Europe and Asia come the "worts": lungwort, barrenwort and navelwort (Pulmonaria, Epimedium and Omphalodes). Wort, incidentally, derives from the old English word, "wyrt", meaning a vegetable or root, and is often applied to plants used for food, medicine or other practical purposes: as in scabwort, birthwort and soapwort.
North America offers many springtime beauties, among them the sky-blue Virginia cowslip (Mertensia pulmonarioides), the pale and starry rue anemone (Anemonella thalictroides), and wake robin (Trillium grandiflorum). The latter has broad, three-petalled, pristine-white flowers, which may take years before they make their first appearance. The saxifrage family gives us the three "Ts": Tiarella (foam flower), Tellima (fringe cups) and Tolmeia - also known as pick-a-back plant, or youth-on-age, because of the new plants that sit on the shoulders of the adults.
North America has its own Dutchman's breeches (Dicentra formosa) - slightly less voluminous than the Asian species. Its epithet formosa, might make you think it was from Taiwan, but in fact it means "handsome" or "beautiful".
Another shade-loving genus that occurs in north America, as well as Europe and Asia, is the Polygonatum, or Solomon's seal clan. The plant most commonly seen in gardens is P. x hybridum, a cross between two species from this side of the Atlantic. It is one of the most elegant plants for shade, with a graceful arching habit and clusters of green-tipped white flowers that dangle like rows of elongated mossy pearls. It is often attacked by the larva of the Solomon's seal sawfly, a smoky-grey caterpillar-like grub that strips the plant until nothing remains but bare stalks. But, although its leaves look unsightly while under assault, the plant doesn't seem to mind, and reappears faithfully each year. Indeed, perhaps the attentions of Phymatocera aterrima keep this sturdy woodlander - which has eagerly running rhizomes - from rampaging through the soil.
Lily-of-the-valley (Convallaria majalis) is closely related, and exhibits the same thuggish tendencies in some gardens. It is one of the first flowers I got to know when I was a very small child, and so it has a special place in my heart. Alas, my soil is too dry for it, but if you have good moist soil, it will make excellent groundcover under trees or at the edge of a wood.
Most plants that are suitable for the shady spots in your garden are natives of deciduous woodlands, so they get the important business of flowering completed before the leaf canopy closes in over them. Often they have generous leaves - brunnera and lungwort, for instance - and so are better equipped to absorb what little sunlight comes their way. Some of the most robust ones are evergreen, and are able to collect light all year round. These include those old stalwarts for dry shade: bergenia, bugle (Ajuga), Corsican and stinking hellebores (Helleborus argutifolius and H. foetidus), periwinkle (Vinca) and some of the hardy geraniums (especially G. endressii, G. macrorrhizum and Geranium x oxonianum).
Some shade plants flower after midsummer, but they are in the minority. Among them are the Japanese anemones (Anemone x hybrida and A. hupehensis var. japonica), some astilbes, and the plants formally known as Cimicifuga racemosa and C. simplex - but now found under the genus of Actea.
Hostas and ferns, of course, are the classic plants for murky areas, the broad, ribbed leaves of the first being complemented by the frondy foliage of the latter. Hostas need moist soil, and may require some protection from slugs and snails, which can turn their gorgeous quilted greenery into lace in just a day or two. The now-fashionable hostas with "yellow" or "gold" leaves (really a pale, and sometimes even sickly green, if you ask me) do not colour up well if deprived of sunlight.
As I mentioned earlier, most shade-lovers are from woodland situations, where decaying leaves make the soil moist and humus-rich. Do try and replicate these conditions in the shadowy parts of your garden. If the soil is good, then all you have to do is mulch with leafmould, garden compost or very well-rotted manure once a year, and let the worms drag it down and dig it in.
If, on the other hand, your ground is dry and poor - which is often the norm for light-starved patches, especially in urban gardens - then you must dig in a heap of organic matter before you even think of planting anything. After planting, mulch to lock in the dampness, and water well. And if the soil dries out, water well again every fortnight or so in summer. Water-misers (and I include myself) don't like this willy-nilly use of the hose pipe, but you need do it only for the first season. Occasional deep watering (as opposed to a light sprinkle) encourages the roots to travel down into the soil and makes them more able to withstand drought in future years.
FURTHER READING
Shade: Planting Solutions for Shady Gardens, by Keith Wiley, published by Mitchell Beazley (£20) and Beth Chatto's Woodland Garden, published by Cassell Illustrated (£16.99)