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For the professional
Perennials for planting in dry soils and beneath tree canopies
Are you faced with having to find the right plants for a location with dry soil? Fortunately, there are many beautiful perennials that will thrive in the most difficult spots – even beneath tree canopies.
Beneath the tree canopy
Soil near the trunks of trees is often dry and very shady. In these situations, you have a choice of many perennials that will enhance the look of these areas. For a tree surrounded by paving material, for example, reserve space around the trunk and fill it with perennials. You might even want the leaf colour of the perennial to complement that of the tree. What about combining a perennial with yellow-green foliage (Origanum vulgare ‘Thumble’s Variety’) beneath a Cigar tree (Catalpa bignonioides ‘Aurea’) with leaves of the same colour? Good plants for locations beneath a tree canopy include Lady’s mantle (Alchemilla), Crane’s bill (Geranium cantabrigiense ‘Cambridge’) and Comfrey (Symphytum grandiflorum). If the soil is dry but not bone dry, Bistort (Persicaria bistorta ‘Superba’) would be a good choice. Evergreen perennials for these conditions include Barrenwort (Epimedium x perralchicum ‘Frohnleiten’), Crane’s bill (Geranium macrorrhizum), Bergenia, Lilyturf (Liriope muscari), Greater periwinkle (Vinca major) and Japanese spurge (Pachysandra terminalis). Flower bulbs also make a beautiful addition.
Did you know that…
- …covering the area beneath the canopy of a street tree with densely planted perennials is safer than using grass or shrubs? After all, mowing the grass can damage the tree’s trunk, and hoeing around shrubs can damage its roots.
- ….essentially nothing – including perennials – will grow under some trees like beech and wingnut?
The largest component of soil in a dry garden is sand. Unlike clay, sand is made up of larger particles with gaps between them so water will drain through and the soil will dry out quickly. To create an attractive planting here, choosing the right perennials is essential. Mediterranean plants actually prefer a sunny spot with dry soil over normal garden soil. Good examples are Yellow camomile (Anthemis tinctoria), Red valerian (Centranthus ruber), Catnip (Nepeta), Globe thistle (Echinops), Baby’s breath (Gypsophila) and Yucca. Some plants are even suitable for spots that are both dry and shady. Examples are the wintergreen Turkish wood spurge (Euphorbia amygdaloides ssp. robbiae), Italian arum (Arum italicum), Bergenia, Spotted deadnettle (Lamium maculatum), Crane’s bill (Geranium macrorrhizum) and Barrenwort (Epimedium x perralchicum ‘Frohnleiten’).
Planting and maintenance
Autumn is an excellent time of year to plant perennials in dry soil. September in particular is when perennials exhibit their strongest growth. This time of cool temperatures and usually substantial rainfall will benefit root development for a better chance of survival. For vigorous growth, it is advisable to provide fertiliser every year. Just after planting a young tree is a good time to plant perennials around its trunk. This way, the tree and the perennials can mature together. When planting perennials around an older tree, care must be taken not to damage the tree’s roots. For this reason, carefully loosen the soil around the tree and use vertically vining perennials such as Clematis (Clematis jouiana ‘Praecox’).