Garden Clippings for November 6, 2021
A dense forest is often not dense. Deep in the centre of the woods the towering trees overhead cast so much shade that the sun never shines on the forest floor. And not much grows where the sun never shines.
The outer edge of a forest where the sun shines is often a thick mumbo jumbo of thistles, wild raspberries, dogwood, sumac and wild cherry that is nearly impossible to penetrate. But once you’ve managed to find your way through, the forest is often so wide open that you could almost play baseball.
For home landscapes, finding plants that grow in dense shade is a challenge. The deeper the shade the greater the challenge.
The variety of perennials that tolerate shade is quite wide, with Hostas topping the list. Hostas offer a seemingly endless array of sizes, flavours, textures and leaf colours. For dense shade, the white margined varieties offer considerable colour. I recommend using mass plantings for dramatic effect.
Other perennials that fare well in deep shade are Bleeding Heart, Brunnera, Ligularia, Barrenwort, Ferns and Lungwort. For medium shaded gardens, try Hellebores, Astilbe, Coral Bells, Trillium and Spiderwort.
Finding an evergreen to grow in deep shade is easy, because there are only three to pick from: Yews, Boxwood and Hemlock.
Yews (Taxus) are my go-to choice when looking for an evergreen that will grow in shade. About Yews I will say they are well-behaved and will grow in a closet. Yews are disease and insect resistant, easy to care for, and easy to prune. They don’t like too much water and prefer poor, well-drained soil over rich damp soil.
The most popular variety of Yew is Hicks Yew, which grows tall and makes a fine hedge, but becomes too large for foundation plantings. On the opposite end is the slow growing Emerald Spreader Yew, growing only a foot high and not much more than 2 feet wide. In the middle is Dense Yew, a good choice for home landscapes because it grows to nearly 4 feet high and wide but easy to keep pruned to any size.
Boxwoods are small growing broadleaf evergreens that are tough as nails. If left alone, boxwoods grow to a haphazard globe shape reaching a diameter of 3 or 4 feet. Prune Boxwoods annually and they are easy to train into a tidy, globe shape. I will often recommend planting Boxwoods below windows where we want little height.
Boxwoods grow equally well in sun or shade. They don’t have fussy soil requirements and don’t need much water. Boxwoods make a neat hedge along a sidewalk or at the front of a landscape border.
Nursery growers have come up with many varieties of Boxwood, all with a similar roundish growth habit. Green Mound is dark green and slightly egg shaped. Green Gem is slower growing with smaller leaves. Green Mountain is slightly taller forming a small cone or pyramid.
For a larger growing, shade tolerant conifer look for Canadian Hemlock. On the Canadian west coast, they become towering giants, but when grown in Ontario, rarely grow higher than 20 feet. For home gardeners, Hemlock can be pruned and kept at any desirable size.
For medium shaded gardens, the following conifers will grow quite nicely: White or Norway Spruce, White Cedars, Mugho Pine, Rhododendron and Holly.