It is my belief that the health of a plant is directly dependent upon the quality of the soil-find out what type of soil a plant needs and you are halfway home. Fortunately, the vast majority of shade-loving plants are shallow-rooted and get first crack at whatever nourishment is applied. I use organic matter, such as shredded leaves and weathered farmyard manure, either slightly dug in or as a mulch. Among other things, the use of such material helps to maintain soil moisture and cuts down on watering. This appears quite acceptable to numerous plants, including primroses, such as cowslip (Primula veris, Zone 3), P. vialii (Zone 5) and the various cultivars of P. x pruhoniciana (Zone 4).
Unfortunately, it is also an ideal environment for my arch-enemy, the slug. I have tried the recommended non-poisonous traps and baits, but to no avail. Though there is now a safe (or so they say) poisonous bait on the market, my main defence is still hand-picking the slugs first thing in the morning. My highest count for one month is 2,244.
My next worse enemy is the earwig. I capture these in all manner of homemade traps, then drop them into hot, soapy water. Earwigs are particularly fond of eating the flowers of my clematis. To trap a thousand earwigs per season at the base of my ‘Henryi' clematis is no surprise. Incidentally, though most clematis respond to sun, they need their roots shaded. This also applies to climbing honeysuckles. I have seen many honeysuckles growing in shade but most-Lonicera ‘Mandarin' (Zone 4) and L. periclymenum ‘Graham Thomas' (Zone 5), for example-like to have their flowering parts in more sunlight.
The most difficult type of shade condition is, I believe, dry shade (often found under maples). Although I have suggested a number of plants worth trying in that situation (see “Dry Shade”, page 79), many of these are more prolific elsewhere. For instance, lily-of-the-valley (Convallaria majalis) does well for me in dry shade, but put it into the damp, woodsy soil it prefers and it can spread like wildfire (I have seen it as the main groundcover in an 80-hectare British woodland). It would be worth investigating whether other rampant growers could be controlled by dry shade.
One of the advantages of deciduous shade trees is that many lovely flowers that require spring sun but summer shade will grow beneath them. Think trout lilies (Erythronium spp.), shooting stars (Dodecatheon spp.), spring beauty (Claytonia caroliniana) and bloodroot (Sanguinaria canadensis). In this environment, I also grow trilliums, Jack-in-the-pulpit, foam flowers, anemones and numerous hostas. Though we are inclined to use plants with good leaf effect in the woodland garden, flowers grown in shade last longer and maintain their colour intensity better than those grown in full sun. Many foliage plants, such as hostas and Brunnera spp., also put on an excellent display of flowers. If you want to boost the floral display a little, plant celandine poppies (Stylophorum diphyllum, Zone 6), large merrybells (Uvularia grandiflora, Zone 3), coral bells (Heuchera sanguinea, Zone 3), violets, woodland phloxes (Phlox divaricata, Zone 4) and, of course, a multitude of primulas.
When thinking of plants for shade, do not forget the ferns, which have few pests or problems and create an ambience of lush maturity. There are ferns for different intensities of light and soil moisture. One fern I like, though do not grow, is the royal fern (Osmunda regalis, Zone 4). It enjoys damp (often wet) shade along with glorious primroses, such as Primula japonica (Zone 3), P. florindae (Zone 6), P. bulleyana (Zone 5) and P. chungensis (Zone 5).
It would be nice to have a garden with areas of both shade and full sun. But beggars can't be choosers, so I will continue to submerge myself in the fascinating and rewarding pastime of shade gardening, and be thankful for it.
Siting your plants
Because the amount and intensity of light are so diverse in a vast country such as ours, plant behaviour varies from one area to another. For instance, when I was gardening in St. John's, Newfoundland, I was able to grow certain plants in full sun that require shade in Truro, Nova Scotia, where I now live. To make things even more interesting, there are numerous new plant introductions for which very little cultural information is available. Learn the characteristics and idiosyncracies of your garden and be brave enough to experiment. Decide whether a plant needs more shade or sun by reading the plant label, consulting a book or magazine or asking for advice from nursery staff or other gardeners. We all learn as we go along.