By Barbara Leach, Horticulture Techniciation, VCE-Roanoke
It is barely spring and already I am thinking fall. My spring garden is much to my liking. It has plenty going on and plenty of color and contrast. Even with the recent frosts, it has bounced back wonderfully. A bigger challenge for most gardeners is that lag time in late summer and fall, when fewer things are in bloom. Many of you may be looking for things that can be planted this spring for some fall color. Our ideas often fall short of our reality, so careful planning is key to good results.
Mums and asters have long been sun-loving perennial standards for fall color. Chrysanthemums can be disappointingly short-lived, however. One must choose varieties carefully to get plants that are reliably perennial and don’t fade into the dust quickly. Preserving some of the heirloom varieties is fun and provides a lot of variation. They tend to be more open and less brittle than some of the newer varieties. Most will be tall. Avoid planting the big showy-flowered florist mums, which are not hardy here. If you do not find mums available in the spring, be sure to plant them as soon as they become available in the fall. You need plenty of time for root establishment before cold weather or they may not come back the following year, even if they are a hardy variety.
Mums require frequent division to keep viable shoots. In spring, lift the whole clump and reset clusters of the “toes” or sprouts coming out around the edge like a halo. Mums also require frequent cutting back to keep them compact and bushy. Cut or pinch them frequently until mid-summer to get the best shaped plants. Mums resent being planted too deeply and like plenty of moisture with good drainage. Taking time to properly prepare the bed prior to planting will help ensure success. Mums are not heavy feeders but do appreciate regular feeding until flower buds are well set and beginning to open. A good balanced organic fertilizer will ensure a steady supply of nutrients without causing them to stretch. Organic fertilizers improve the soil structure so are a wonderful choice in clay soils.
When I think of asters I think of country gardens where their sprawling gangly looks fit in well with the tall grasses of adjacent meadows. Suburban and urban gardens can quickly be overwhelmed by loose irregular form perennials, however. Some varieties are 3’-6’ tall and will not stand unless staked. A better choice for the modern smaller garden is to look for some of the new dwarf hybrids. Look, also, for disease resistance. It gets hard to put hybrids into groups since they come from mixed parentage, but generally New York asters are shorter than New England and some of the Smooth asters are short. Look for varieties like Woods Blue or Pink, Alert, Flora’s Delight, Professor Anton Kippenberg, October Skies, Purple Dome, Wonder of Staffa, Triumph, Mὄnch and many others.
Like mums, asters need plenty of moisture and well drained soils. They are generally longer lived than mums and pretty tough. If your hardy asters do not come back and you planted them in spring or early fall then you might want to look to your winter drainage as the culprit, since they should have had enough time to establish. Cold and wet soils can mean the kiss of death. With better amending or planting on mounds you will likely be more successful.
For shade try Chelone (Turtlehead), Cimicifuga (Bugbane or Snakeroot) or Japanese Anemones. All require regular watering. Dead-heading will extend the blooming season.
With some careful planning and shopping now, you can have a late summer/fall garden with lots of excitement.