Our backyard is dominated by mature White Pines (Pinus strobus), some on our property and some on the neighbors’ properties, and a mature Green Ash (Fraxinus pennslyvanica) and an adolescent Pin Oak (Quercus palustris) . The soil under the trees is quite dry on the north side of the property and very wet on the south side as four properties drained down to that corner. The neighbors’ gardening solutions have been either to abandon the area under the trees to weeds and whatever volunteer shrubs and small trees that happened to appear or to grow lawn as far back as they can, with small , struggling shade gardens at the very back. The neighbors’ pines have all lost their lower limbs at least 15 feet up the trees but ours still have branches sweeping down to about 6 feet of the ground. (In case you’re not familiar with White Pines, their needles are long and soft and, unlike most conifers, very pleasant to brush against! The pines drop massive quantities of needles every October.) Woodland gardening was the obvious thing to try in these conditions so that is what we began in 2000, our first full year in this location.
First of all, let me be clear on what I’m talking about. My ‘woodland’ is contained within the back part of our suburban, zone 6a southern Ontario 75’x155’ property. I’m not talking about acres of woods! In total, my ‘woodland garden’ is 75’ wide and about 25’ deep. The dry side is slightly more than half the area - about 35-40 feet of the width. My goal is to make the area look like a natural woodland but with more color and a greater variety of interesting plants. Some of the plants are native plants but many are not. If a plant will grow in the conditions I have and look appropriate in the garden, I plant it!
Color in a woodland garden tends to be a subtle thing. From a distance, what you predominately see is shades of green; white is also quite visible and strong shades of blue (e.g. forget-me-not blue and the blues of Brunnera.) The picture (taken from the back porch) at the end of this article is a good illustration - the most visible colors are the varying greens of the Ash and the pines, the white narcissuses in the blueberry bed and the white flowers on the Black Jetbead shrub (Rhodotypos scandens.) In mid summer, the white flowers on the Elders (Sambucus canadensis) by the shed and the False Spirea (Sorbaire sorbifolia) are visible, followed by the white flowers of the hydrangeas at the back of the blueberry bed. Woodland flowers tend to be low to the ground and best viewed from within the garden along the paths or from the edge of the lawn at the front of the garden. A woodland garden is a peaceful (except for the summer mosquitoes!), subtle, contemplative garden that relies heavily on foliage and charmingly pleasing little surprises (such as the hardy cyclamen blooms that pop up unexpectedly in September) that you encounter as you walk through the garden.
This year will be our third summer in this location and the garden is finally beginning to look less bare. It has been a trial and error situation to find things that will grow in the conditions we have.
Some of the important general considerations in our little woodland garden are:
One of the basic things to understand about a woodland is that it has five layers: the canopy layer of tall trees (the pines and the ash a short distance away on the lawn); understory trees- shorter trees that will grow in the shade of taller trees; shrubs; herbaceous perennials; and groundcovers. We only had a canopy layer at the beginning and weeds for the herbaceous/groundcover layers! In the first summer in the garden (2000) we added mainly perennials, three rhododendrons and a few (very few) other shrubs.. The end result was very peculiar-looking - the absence of a good shrub layer was a very noticeable defect! In 2001 we added more shrubs and more perennials and some groundcovers. The shrubs improved things but they need to mature in size a bit more before the improvement will be substantial and I’m continuing to add more shrubs. As yet we only have one understory tree - which is not yet a tree; it’s a seedling of a neighbor’s Bloodgood Japanese Maple (we think…) that we found growing in the lawn in 2000 and transplanted into the woodland. It seems to be thriving but is still under 12” tall! Clearly growing a Japanese Maple from seed is a long-term project….
Soil and Moisture
The soil was very dry under the trees on the north side - only a very heavy rain penetrates the pine canopy. Snow does drift under in the winter so spring conditions are reasonable. However, summer heat and drought and the pines’ water needs means the soil gets bone dry by mid summer. After one year of trying to hand water the plantings, we clearly needed a better solution.
Soaker hoses entered my life at this point. I laid about 300 feet of them under the trees. (There are two 100’ hoses connected to one two-pronged hose connector and one 100’ hose on its own connection.) I made sure the hoses ran past the base of all shrubs and any perennials that are not solidly drought tolerant. All new plants are planted as close as possible to a hose. If they don’t mind drier conditions, they naturally spread out; otherwise they stay close to the hose. To plant the rhododendrons in 2000 we made a raised bank along the back fence from layers of pine needles and oak leaves, triple mix and coarse peat. The soaker hose runs along the back of the bed to provide moisture. Shrubs that prefer moist conditions, such as hydrangeas and Summersweet (Clethra alnifolia) are planted within a loop of the hose so they get extra water. In the driest part of the summer 2001 (the first year with the hoses), we watered once a week for about an hour at a time. No plants were lost to the drought last year. I added soaker hoses to all my beds along the foundation of the house (where the roof overhang prevents rain from getting to the beds) and down the driveway where it is sunny and hot. We’ve just created a large new bed on the front lawn this spring and there are 250 feet of hoses in it and another 100 feet in a new herb bed. They are an inexpensive, practical and efficient way to water and I recommend them highly. They allow me to plant things that would not otherwise grow in dry conditions.
The wetter south side of the property doesn’t need hoses, although I did need to water twice with sprinklers during last year’s drought. I call this area my ‘wet corner’ because it is very wet indeed in the spring. The soil is heavy clay and retains moisture. In 2000, any hole dug in that area in the spring immediately filled up with water. In 2001 we added 4-6” of good top dressing soil mix on top (maybe not the ideal way to proceed but it works…) and conditions have much improved. Moist shade is much easier to garden in than dry and the wet side is turning into a satisfactory garden much faster than the dry side.
Adding organic matter to the woodland, particularly on the dry side, is a priority so all fallen pine needles and leaves from the Ash and Oak are allowed to remain where they fall. Regular additions of compost to supplement the natural leaf litter are also important. The soil under the trees is improving but it will take time for it to build up to an acceptable condition.
Weeds and maintenance
Garlic Mustard Weed (Alliaria petiolata) is the bane of my existence these days! It is a prolific seeder and runs rampant in the ‘abandoned’ areas of the neighbors’ properties which means I get plenty of seeds. Yellow Avens (Geum aleppicum) and Black Medick (Medicago lupulina) are a close second. In Y2000, I weeded non-stop! By the time I weeded my way from one side to the other, it was time to start over again. In 2001, I did a thorough spring weeding in late April and then just needed to pull new seedlings from time to time as they appeared. In addition to ‘true’ weeds, I’m constantly ripping out Lily-of-the-Valley that the previous owner had planted. It does well (too well!) in both the wet and dry sides, but is too invasive to be left in the garden. On the wetter side, the violets have self seeded prolifically and need regular weeding out. Garlic Mustard Weed has very similar looking leaves and seems to deliberately take up residence with the violets. Since I have far too many of both, I just treat the pair as weeds and rip them both out!
The intense weeding in 2000 was made difficult by the size of the garden so early in the spring 2001, we made paths through the garden by laying a mix of 50/50 coarse sand and pine bark mulch on top of the ground in a layer about 2” deep and 30-36” wide and flattened it with a water filled roller. The mixture has settled in nicely to make a path firm enough for my walker to negotiate easily (I am physically disabled…) and the material blends in well with the woodland setting. The paths make accessing the area easier for weeding, planting and viewing the garden from inside the garden itself.
The light levels vary considerably within the garden. The garden runs roughly northwest-southeast. The outer edges of the garden get quite a lot of morning sun, especially until mid June when the pines replace the needles that fell in the previous fall. The center of the garden, where the blueberries and rhubarb are, gets about 5 hours of good sun in the spring and early summer before our ash and trees on the property of neighbor behind us to the south leaf out. The pines on the property behind us to the south have lost all their lower limbs which improves the level of available light, especially in the wetter part of the garden where there are no large trees on our property. The light tapers off until, at the very back of the property, the shade is quite dense. Some sun loving plants, like mallows, have done surprisingly well on the edge of the woodland and most plants that say ‘part shade’ grow easily. For the deepest shade and driest conditions, Beacon Silver Lamium does a good job of lighting up the area with it’s luminous leaves. It spreads quickly but, so far at least, has been easy to rip out when it strays. Sweet Woodruff also takes very dry, dark conditions but spreads vigorously so is restricted to the least hospitable areas.
Trying to turn the somewhat difficult conditions under the trees into a garden has certainly been a learning experience and is obviously a long-term project. Too much of the area still looks empty and bare although there are many plants and bushes there now. My guess is that it will take another 3 years or so before it truly begins to look like a garden. On May 31, 2002, the view from the back porch looked like this:
The spring color from bulbs has mostly faded and summer color hasn’t begun yet so green, the primary woodland color, is dominant.
A more detailed discussion of what’s in the garden is the subject of two separate articles - one on the dry side (the right-hand side and one on the ‘wet corner’, on the left side of the (ugly!) shed. At the time of writing these articles, there are over 140 different types of plants under the trees and I’ve still got room for more!