In The Garden: Head For Cover
While we were worshiping to the sun gods back in February, some of us may now be getting fed up with the heat. With high temperatures come increased UV rays, so it makes sense to seek out shady spots that provide some reprieve.
It’s under the shade of a leafy tree where we’ll experience temperatures that are five to 12 degrees cooler. The moisture it evaporates provides a cooling effect, so it’s no wonder we naturally migrate to these prime locations to have a picnic, read a book or take a nap.
A Shady Deal | It’s a good time to consider options for a shade garden, especially for under those trees on the north side of your house. I have a short list of favourites that are ideal for dappled shade – plants that prefer a sun/shade mix, but don’t like the hot/dry sun of mid afternoon.
Astilbe | Also known as False Spirea and Feather Flower, this plant injects a burst of colour for a prolonged stretch of time – from late spring and throughout the summer. The brightly coloured blossoms are electrifying in intensity, and grow from 30 to 80 centimetres high. They prefer an open, peaty soil, but once they dry out, it’s difficult to rehydrate them. To prevent them from doing so, be sure to mulch with five centimetres of shredded cedar bark.
Rhododendrons | ‘Rhodies’, as they are affectionately known in the business, hold a special place in the shade garden – but there are some secrets. For one, they love an acid soil, which is opposite to the alkaline stuff most of us put up with in the GTA. Always plant your rhododendrons in an open, sandy soil, mixed with finely ground pine bark – about 30 per cent by volume. Add about four tablespoons of garden sulphur (to help to acidify the soil) about every six weeks throughout the summer and into the early fall. Keep in mind that you’re not fertilizing them, per se, you’re changing the pH of the soil. For a foolproof garden performance, I recommend the winter tough ‘PJM’ varieties – purple flowers, with early spring blooms that are hardy to zone 4 (Ottawa).
Boxwood | Buxus is a broad-leafed evergreen that performs very well in all areas, up to zone 4. Boxwood is an evergreen, so treat it with a humusbased soil of peat or compost, and fertilize every few weeks with an evergreen food, like 30-10-10, until the middle of the summer. There have been many amazing boxwood hybrids that have been introduced over the years, which provide a deeper colour and a more finely textured foliage, versus the original version of Korean Boxwood.
Oregon Grape | Native to British Columbia, the Mahonia Aquifolium grows quite well in zone 5 and 6 gardens (including Barrie). This plant features holly-like leaves that remain on the plant throughout the winter, and are then replaced as new growth occurs each spring. They have a delightful yellow flower in the spring, and a dense, shrubby growth habit. Oregon Grape matures to about one metre high, and equally as wide. I like it best when planted on the fringe of a hardwood bush, or under the shade of shrubs or a tall deciduous tree.
Mark Cullen is an expert gardener, author and broadcaster. Check out his new book The New Canadian Garden published by Dundurn Press. Follow him on Facebook and on Twitter @MarkCullen4. MarkCullen.com