We all have them: holes that exist in our perennial borders. I’m not talking about the holes caused by squirrels or voles; rather I’m talking about those gaps we never seem able to fill. The holes that never seem to exist at the Sarah P. Duke Gardens or the JC Raulston Arboretum—I’m referring to those holes that we amateur gardeners produce.
The perennial sun border holes are relatively easy to fill. We can stick an allium here and there, sometimes a hardy Hippeastrum, or maybe one of the smaller echinaceas, like ‘Kim’s Knee High’. It is the shade garden gaps that, for me, cause the problems. Gradually throughout the years as my garden has gotten shadier, I have slowly discovered some plant combinations that please me.
I have a fence, which means I can grow lots of hosta. But situating hosta is tricky because it takes hosta about three years before it reaches adulthood. Consequently there are gaps between the young hostas. I enjoy planting Louisiana irises throughout the hostas. I like the combination of the vertical and horizontal positions of these two plants and I love the purple flowers in contrast to the green variations of the hosta leaves. When the hosta reaches its full size and begins to crowd out the irises, I simple move the irises to another place in the garden. Irises are very easy to transplant—even easier than daylilies—so this is not an arduous task. Hosta wants the same light shade where the Louisiana iris grows, so these two pair up well.
Ask me to your house for dinner and you will probably end up with a Spigellia marilandica as a house gift. This is a nondescript looking plant that easily fits into the slimmest of holes—nondescript that is until it produces blooms of small red stars with golden centers. This plant will grow in size until it becomes a smallish clump, smaller than a daylily clump, so it never threatens the plants next door. Appearing in May, the flowers never cease to charm me.
What can I say about Begonia grandis except I love it, I love it, I love it. This hardy begonia is hardy to zone 5 and always comes back for me. Yes, it spreads through its seeds and its bulbils, but it never overtakes another plant. Instead, it cuddles around my hostas and my camellias. It wants to cuddle around my roses but here I take a stand, as I never know if the roses will regard this as tiresome competition. In late July, when little is blooming, it’s hot and humid, and summer begins to seem a bit tiresome, the begonias put on a show and bloom for a good six weeks. Their flowers are small and delicate—which is one of the reasons you welcome their spread. Plant Begonia grandis in one hole and it will tactfully find others to plug up.
Another plant that is good at filling up holes is Polygonatum odoatum thunbergii ‘variegatum’, the ever-reliable Solomon’s seal. This plant is flexible in its light needs, growing anywhere from a partly sunny location to a shady one. I’ve never seen a plant that wasn’t enhanced by the variegated green and white leaves except perhaps a variegated hosta. This is a plant that returns reliably year after year and quietly does it own thing, making it an ideal plugger of holes.
Ten years ago I bought a flat of asparagus ferns and spread them throughout the garden in an effort to fill in the gaps. They turn a lovely silvery color after the first frost, never seed throughout the garden, and look lovely and feathery when placed next to the roses or daylilies. I know that according to the Internet these are zone 9 plants—I can only say they return year after year.
Today my garden gaps are getting fewer and farther between: a good thing according to Martha.
Kit Flynn has been an Extension Master Gardener in Durham for thirteen years. Besides being a compulsive gardener in Chapel Hill, she also writes gardening articles for the Durham County Extension Master Gardener newsletter and for “Senior Correspondent,” an online magazine.