One question often heard is “why plant shrubs instead of trees?” At Macphail Woods, we use a combination of trees and shrubs in all our plantings. In addition to the diversity of plant species, we gain a variety of feeding and resting areas, food sources and nesting habitat.
Here are some of the areas where we find native shrubs to be most useful and the reasons for using certain species:
Controlling erosion along streams:
Species such as willow and alder are very hardy, easily grown and can tolerate the harsh conditions along streams. At Macphail Woods, we are experimenting with a wide variety of native shrubs to stop silt from entering the stream.
Creating windbreaks and hedgerows:
Instead of one or two species of trees that can be susceptible to insect infestations or diseases, a mixed planting of hardwood and softwood trees, plus a variety of shrubs, can make an excellent windbreak. Planting serviceberry, hawthorn and alder ensures a wider variety of animals will use the area through the year and increase its attractiveness.
Improving fish habitat:
Many of the best fishing areas are streams lined with alders that overhang the water and create shade. Depending on the conditions of the stream, other species such as willow and red osier dogwood can also provide shade.
Improving other wildlife habitat:
Shrubs play very important roles in the lives of many animals, providing food, protection, and nesting sites. A dense clump of hawthorn provides excellent protection for smaller birds seeking to escape hawks or domestic cats. Shrubs also provide food throughout the year for many species. Willow buds and catkins are eaten by ruffed grouse in the early spring, the twigs are heavily browsed by snowshoe hare, and beaver use the branches for building dams and the bark for food. Shrubs also diversify the heights found within a forest, important since some birds feed at one level and rest or nest at another.
Alders, the scourge of many Island farmers, are excellent shrubs for improving soil. They fix nitrogen in root nodules and their falling leaves are very high in nitrogen. The natural fertility of forests depends largely on nutrients contained within the litter (fallen twigs, leaves, fruits) and the rate of decomposition. Shrub leaves generally have high contents of potassium, phosphorus and nitrogen and add complexity and quantity to the annual addition of organic matter to the soil. This enhances the quality of organic matter which stabilises soil and improves moisture retention, nutrient retention, nutrient cycling and aeration.
Some of the best landscaping plants are native shrubs. They are hardy, inexpensive (or free if you grow your own), and serve many different functions at the same time. The addition of Red Osier Dogwood to an area gives showy flowers in the spring, dense green colour all summer, food and protection for a wide variety of wildlife, and attractive red twigs throughout the year that are especially appealing in winter. Staghorn sumac is another year-round performer, with its exotic shape and fuzzy twigs most noticeable during the winter, compound leaves in the spring and summer that turn a brilliant scarlet during the fall, and long red spires of seed. An assortment of shrubs provides an endless succession of leaves, flowers, seeds, buds, colours and shapes – visual reminders of the complexity of natural systems.
Other reasons we might not be aware of:
Gardeners are realizing the beneficial effects of growing different species of plants together, to deter predators and improve yields. Without a doubt, shrubs have important roles to play that we do not yet understand. Do they attract birds that in turn prey on tree “pests”? Do they diversify a forest to such an extent that they deter large numbers of predators? We do know that they reduce the rate at which forests and soils dry out, reduce wind movement through forests, and help regulate run-off from rainfall and melting snow. Do they help lessen the risk of fire? Again, the edible and medicinal values of many shrubs are well-known, but little work has been done on a large number of others. It points out just how much we have to learn.
Bare Root Stock
Bare root stock should be planted in spring before the leaves open or the new needles have started growing. When buying stock, time the purchase for when you have the time to plant. Sometimes this is impossible or impractical as when planting large numbers of trees or in case of poor weather. Plants can be held for awhile in the ground by “heeling-in”.
Heeling-In. Choose an out of the way location, with some shade, where you can dig holes large enough to bury the roots. Bundles of trees and shrubs can be heeled-in together. Water well and mulch to keep the soil moist. If keeping plants heeled-in for more than a few days, be sure the soil is damp and covering the roots. Keep the plants in the ground until ready to plant out.
Never let the roots dry out. Soak bare root stock in buckets of water overnight before planting. Keep the trees and shrubs in the buckets of water as you check over the roots and while preparing holes and planting. Check the roots and prune any that are broken, split or scraped. Use sharp by-pass pruners to ensure a clean cut. Prune roots of small stock (under 12 inches 30 cm) to about 6 inches (15 cm). Larger trees and shrubs will need more root and a larger hole than smaller stock. Prune any roots that are circling the trunk, if they will not straighten. Keep roots wet: make a “slurry”, a soupy mix of water and soil. Dip roots into it while getting ready to plant. The slurry will stick to the roots and keep them from drying out.
Dig a straight sided hole about 12 inches (30 cm) deep for every 8 inches (20 cm) of root depth. If possible, put the topsoil on a cloth or tarp to make refilling the hole easier. Dig a wide hole to allow unrestricted lateral root growth. Even small trees and shrubs will benefit from a 1-2 foot (30-60 cm) wide hole. All plants should have a hole at least twice as wide as the diameter of the root mass. Rough up the sides of the hole and place a mound of topsoil or compost at the bottom. Spread the roots over the mound. The plant should be at the same soil depth or slightly higher than it grew in the nursery (look for a colour change at the root collar). Fill in the hole and firmly tamp to remove any air pockets. Water deeply and mulch with a 3 inch (7.5 cm) layer of leaf mould or wood chips. Keep mulch 3-4 inches (7.5-10 cm) away from the stem to discourage damage from rodents during the winter.
If bare root stock is in leaf when it is planted, prune 30% of each branch, taking care not to prune the leader (main stem). This reduces the moisture loss from the plant and helps ensure survival. Small trees usually do not need to be staked but if size requires it, use two stakes and rubber tubing, hose or nylon stockings. Do not use wire or rope as they will cut into the stem and cause serious damage. Remove stakes and ties by the second growing season.
Timing is not quite as important for container grown seedlings as for bare root stock. Container stock can be successfully planted throughout the growing season. Container size is generally one litre and up. Hardwood seedlings in containers need special attention if planting out when growth is already well underway. Shade plantings are easier to maintain than plantings in full sun, which will need to be watered regularly and kept well mulched. Water the container plants well the day before planting. To remove the plant from the container, turn the container overwith the stem between your fingers. Give the container bottom a good rap with the palm of your hand and catch the root ball as it slides out. Be careful not to damage the stem. Prune any roots that are circling the trunk which might eventually girdle the tree. Using a screwdriver, pull some of the larger roots away from the root ball to help stimulate new growth.
Dig a hole with straight sides, about 8 inches (20 cm) deep for every 12 inches (30 cm) of container depth. If possible, put the topsoil on a cloth or tarp to make refilling the hole easier. Dig a wide hole, at least 2-3 times the container width to allow wider, unrestricted root growth. Rough up the sides of the hole and place some topsoil or compost on the bottom of the hole. The plant should be at the same soil depth as it was in the container. Fill in the rest of the hole and tamp well to remove air pockets. Water deeply and mulch with a 3 inch (7.5 cm) layer of leaf mould or wood chips. Keep mulch 3-4 inches (7.5-10 cm) away from the stem to discourage rodent damage during winter. Container stock will rarely need pruning, especially if the plants are young. Prune lightly for shape, if desired, or to remove damaged branches. Do not prune the central leader.
Trees and Shrubs Need: