Shady parts of the garden are often welcome in the summer, as cool refuges from the heat. But most plants don’t find them so welcoming. When we put in a new garden it begins with almost everything growing in the sun, but as time passes and the trees and larger shrubs grow up, the areas beneath them become shadier and shadier. If you move into an established garden with mature trees, they are certainly a great asset, but it is hard to garden beneath them, in areas that are dark and also often dry.
For plants it’s worth noting the difference between shady areas. Some shade comes from the shadow of buildings or trees – you are in the shade, but if you look up you can see the sky. These areas are much easier to plant in, and many shrubs described as ‘suitable for partial shade’ will grow well in them. It is the areas directly beneath trees – look up and you see branches and leaves – that are much more difficult to plant. Most of the useful light has been filtered out by passing through those overhead leaves, and so plants really struggle to survive in light where most of its value has already been removed. These are the difficult areas to plant – but don’t worry, there are still some plants that have evolved to survive in those areas, and they are the ones to plant.
Groundcover Plants for Deep Shade
Here are some plants that will grow even in deep shade, and that will spread and cover these difficult areas. First, a couple of reliable plants for colder parts of the country, and then two for hotter areas:
E.A. Bowles was a famous early-20th century English gardener who left us this plant as part of his legacy – without a doubt this is the toughest and most reliable groundcover for deep shade. It will grow almost anywhere in the country, and it quickly forms a dense mat of evergreen foliage in the most difficult spots. This particular form is more compact and less invasive than the original wild plant it was selected from, Vinca minor. It has small, glossy leaves that are rich green, and carpeting the ground beneath trees it is always attractive. In spring it is smothered in beautiful blue flowers, creating a gorgeous color-carpet. Pest free and usually left alone by deer, this is the number-one choice for easy ground cover in a wide range of conditions. Plant 3 feet apart, and you will quickly cover even large areas.
Emerald Gaiety Wintercreeper
Shady areas are dark, so brightly-colored foliage makes sense. This plant, a form of the Japanese plant Euonymus fortunei, grows across the ground, and forms mounds up to 3 feet high. One plant will cover an area about 6 feet across, so it’s the perfect choice for large areas. The small emerald-green leaves are edged with a broad band of white, creating a bright effect. This plant grows well in colder areas and zone 6 is about its southern limit. Plants take a little long than Periwinkle to cover an area, but once established they are very durable, and just need a light trim every year to keep them compact. The solid cover created is pretty much weed-proof, so very little care is needed.
Royal Purple Liriope
This grass-like plant (Liriope muscari), also called Lily Turf, is a great choice for warm areas, growing in zones 6 to 10. It is very versatile, and it will grow well in most light-conditions. It forms a mat of upright, arching leaves between 12 and 18 inches tall, which are a rich purple color, making a great contrast with the green of your other plants. It forms a dense covering over the ground, and in late summer and fall there is the bonus of spikes of deep- blue flowers nestling among the leaves.
You need to live in a frost-free area, but if you do, this popular house-plant (Chlorophytum comosum) makes a terrific ground cover for shady places. It quickly forms dense clumps of narrow upright leaves, which are brightly striped in creamy-white. New plants form at the ends of the flower stems, and these naturally fall to the ground and root, or you can help fill gaps when the plants are new by taking them off and planting them. Even in colder areas the plants grow quickly, so they can be used as a temporary summer ground cover too. Once established plants are drought-resistant too – especially useful in hot areas.
Soil Preparation for Groundcover
Preparing planting areas is always important, but it is extra-necessary when planting under trees. The ground is usually full of tree roots, which have already taken lots of the nutrients, and quickly take up any available water too. We need to create an environment that gives our new plants a chance to become established without competition – once established they will be able to cope with conditions that would have killed them when newly planted.
What kind of trees are you planting under? Most deciduous trees can handle losing a bit of root, and even having the soil level raised a few inches. Evergreens, especially pines, are more sensitive to root disturbance and covering, so for them, limit your preparation to creating planting holes for each individual groundcover plant. Under other trees you can prepare the whole area more thoroughly, which give the new plants the best start.
Begin by covering the planting site with a 4-inch layer of organic material – compost or manure is best. Then with a sharp spade dig it into the ground, removing small roots as you go. Roots an inch or less in diameter can be safely cut out, but you need to be more cautious with thicker ones – try to leave them in place and just dig around them. You can also add a few inches of fresh soil, and you should, with some work, be able to prepare a planting area more-or-less free of roots. It will take the trees a couple of seasons to re-establish in this soil, by which time your groundcover plants will be well-rooted, and able to compete successfully.
Caring for New Groundcover Plants
Areas beneath trees dry out fast – so you need to water thoroughly every few days in spring and summer. As well, use liquid fertilizer every couple of weeks. Hose-end attachments are the perfect way to water and feed at the same time. Liquid fertilizers are absorbed through leaves as well as roots, so you are feeding directly, without competition from the tree roots. You will soon see new growth and new shoots spreading, and in a couple of seasons the area should be looking great. You have added a whole new level to your garden and created a lush landscape out of barren earth.
Established areas of ground cover should be top-dressed every couple of years with organic material. If you can shred the leaves from your trees in fall and put it back among the ground cover, it’s the perfect way to dispose of your leaves and feed your groundcover plants at the same time.