Choosing plants

Categories Advice and inspirationPosted on

When choosing plants for the garden, I can’t recommend browsing garden books or magazines enough. You can’t imagine something you have never seen. I have an extensive collection of books and magazines that I’m happy to lend to d.i.y.ers. I’ve always found it helpful to look through images together with my clients. It helps me to understand their tastes and preferences when these can be hard to articulate but easy to show. I also use this as an opportunity for suggesting how these styles might be realized in the context of their gardens.

Generally garden plants (other than woody shrubs and trees) are mostly perennials, that is, they return every year and go through an annual cycle of emerging from the ground, growing actively,  blooming, and then declining (some rather messily, others with brilliance) into winter dormancy again. The other type of plant is the annual, these are the ones that you replant every year or grow from last year’s scattered seeds. (Leaving out the biennial and perennial self-seeders….) Annuals don’t overwinter and generally grow quickly and flower continuously to get the maximum number of their seeds scattered before they are killed by frost. They can be inserted into a garden for extra bloom, but are less satisfying to grow. In my mind, a  garden is not a thing that one “has” but is a constantly changing place in which one becomes aware of the momentary and transitory aspect of life as it is right now: the trees, shrubs and perennials are always at a particular stage in their annual cycle. We see the foliage emerging, tender and full of promise; it unfurls more with each day that passes; we enjoy seeing the buds and feeling anticipation; the glory of the blooms — and their delicacy; the gentle fading or blaze of colour as plants prepare for colder temperatures and winter hibernation. Annuals are generally valued for the opposite reason: they remain in bloom for the whole summer. One “has” them blooming all the time. The flowers of perennials are a gift, the momentary expression of the stage of their lives they are at right now.

Look in other gardens for interesting plants, for ideas of where to plant them; gardeners are always watching what is happening in other gardens and in nature. When you find a plant that interests you, that you might want to grow in your garden:

  • check its hardiness rating (standardized number system from 1-10, with 1 the coldest and 10 the hottest climates). This will tell you if the plant can survive the winter here and endure the heat of our summers. Toronto is in zone 6, which means that a plant hardy to zone 6 will generally survive here, especially if given the conditions it enjoys most in other respects (water availability, soil type, sunlight).
  • check the requirements that the plant has for light: do you have space for it in the conditions of sunlight that it wants? This is not as critical as hardiness, but in general, if a plant wants full sun, it will be happiest growing where it gets six or more hours direct sun including the hot afternoon sun. The amount of light a particular area of the garden will get can be modified only to some degree in the short-term. Because trees and shrubs shade the garden, the light conditions will naturally be subject to change: when trees grow larger, creating more shade, or when limbs or shrubs are removed, allowing more light to reach plants at ground-level. The removal of low-hanging tree limbs to raise the tree canopy, called limbing-up, can allow more light to penetrate, benefiting other plants, even if the area remains shaded.
  • check the soil requirements: often this is listed as a drainage requirement because many heat-loving plants will sulk if their roots sit in wet soil for any length of time. This factor can be manipulated by amending the soil in various ways. In general many plants will be happy in “loamy” soil, that is a soil that contains lots of organic matter (compost, composted manure, peat) and doesn’t have too much clay or sand. Low lying areas that collect water will suit particular plants that will grow lush in these conditions, while other plants will be stressed by the excess moisture and not grow well, looking generally unhappy. Making plants that require excellent drainage happy in a heavy clay soil will involve a lot of work, including getting rid of large amounts of the clay. I encourage gardeners to begin by recognizing the conditions they have, improving the soil with organic matter, and choosing plants that will be successful there. On the other hand, most avid gardeners will try to grow things that want different conditions than the ones they have in their gardens and are willing to modify the soil to some extent to do so. Daffodils, for example, want good drainage and dry conditions in summer, a state of affairs that is difficult to manage on the clay soil that plagues many Toronto gardeners. But it is hard to resist growing these quintessential spring bloomers and I keep trying each fall with new patches in which I add sand, mulch, and even vermiculite to the planting holes. With only moderate success.
  • Research. Find plants that will be happy and will satisfy your plant cravings. Often there are some cultivars or varieties that are more tolerant of your particular conditions, while still giving the same satisfactions as their more fussy siblings or cousins. These might be difficult to find at first, but by checking new nurseries and keeping a watch for these less common varieties over several years, one is often rewarded. In general, a more specialized nursery or garden centre will carry more interesting plants than a seasonal department of a big box or grocery store. It will also be staffed more professionally ensuring that you get good advice and that the plants you buy will have been well looked after and hence establish more successfully in your garden. Since our time is always limited, it is worth paying more for healthier plants. But like everyone, I can’t resist a bargain, even in a July heat wave. I’ve also learned that these remaindered plants have (at best) a 50/50 chance of making it.