Last call for winter planning!
It seems a bit upside down to think about winter interest in your garden right now when spring is at our doorstep. Yet, this is our last chance to see the bones, or structure, of our gardens before foliage and flowers arrive!
Many designers say one of the calling cards of a great garden is four seasons of interest -- plants that stand out in spring, summer, fall and winter. Winter can be the most challenging season to get that interest, yet one that can be just as magical as the others.
This photo of mountain mint, red twig dogwood and an evergreen was taken last week in February. Now that is winter interest! There are a couple of things that really make this combo work. First, the stand of mountain mint is thick adding incredible texture provided by a mass of seed heads. That density provides a lot of presence. Then, siting both the mountain mint and red twig dogwood in front of a darker background, an evergreen, ensures those plants really catch your eye. This is a great "formula" for winter interest: perennial layer, shrub layer and an evergreen layer.
The best part is this is a very versatile combo of plants, each of which are easy to grow. The plants are also widely available.
The Perennial Layer
Short toothed mountain mint (Pycnanthemum muticum) is a terrific perennial for pollinators and winter interest. This perennial grows to about three feet high. It will grow in sun and part shade. It thrives in moist soils but grows easily in average and dry soils.
There are three commonly available mountain mints. Short toothed, described above, hoary mountain mint (Pycnanthemum incanum) and slender mountain mint (Pycnanthemum tenuifolium). There is a fourth, Virginia mountain mint (Pycnanthemum virginiana) that also looks to be similar. I don't come across that one very often but I know many of you do. These would all work for winter interest and are similar from a design standpoint.
Short toothed mountain mint is particularly good for moist soils. Slender mountain mint is particularly good for drier soils. For a deeper dive on mountain mint, check out this post from Rutgers University.
Mountain mint is available at many native plant nurseries, some garden centers and by mail. Pollen Nation has slender mountain mint and hoary mountain mint. Plant More Natives has short toothed mountain mint.
From listening to native plant garden designers, I have learned they often start with plugs, planted fairly densely, every 6" or so, both to crowd out weeds and to create stands of perennials that look like the one at the top. Also, some perennials purchased in quart or gallon sized pots also really lend themselves to being divided into more plants right away. Mountain mint is one of those. Water the plant in the pot well and remove it from the container. Once the plant is out of the container, you can gently tease the roots apart and divide it into two or even three plants sometimes.
The Shrub Layer
I do not know which variety of red twig dogwood is in the top photo though I'd guess it is a cultivar based on how brilliantly red the twigs are. The straight species of our native red twig dogwood (Cornus sericea) would be just as effective. This shrub thrives in moist soils and can grow in average soil as well. It grows in full sun or part shade. To maintain the bright red younger stems, prune out a third of the oldest stems each year or cut it back to about a foot or so very three years.
Straight species red twig dogwoods are commonly available at native plant nurseries and sometimes at garden centers. Garden centers often sell cultivars of red twig dogwood. By mail, they are available from Direct Natives,
The Evergreen Layer
For those of us who already have ornamental or non-native evergreen shrubs like yew (Taxus baccata), cherry laurel (Prunus laurocerasus), or asian and english hollies (Ilex aquifolium) that we aren't ready to remove, they can be the perfect backdrop for a native perennial and shrub layer. It's a great way to add native plants to an already established garden.
If you want to add the native evergreen layer too, American hollies (Ilex opaca), eastern red cedars (Juniperus Virginiana) and northern white cedars (Thuja occidentalis) would all work to provide that dark green background. All of these are easy to grow in sun or part shade. American hollies and eastern red cedars are commonly available at native plant nurseries. Northern white cedar is often available at garden centers. American hollies and northern white cedars are available by mail from Direct Native Plants.
Whether you are planting yourself or hiring a landscaper, this should be a very doable approach for adding winter interest. You could do this with one evergreen, one red twig dogwood and several perennials in a corner or you could plant it on a larger scale by planting several trees and shrubs with many perennials or even rows of these three plants along a fence or border.
A last look for your winter garden? It won't be back for some time!