An ecological gardener’s to-do list is short in autumn, but here’s a few tips to remind you what to do – and what not to do – to maintain the naturalistic qualities of landscapes, regardless of how large or small they are. A garden can provide both beauty and habitat value all winter long.
1. Foster wildlife by leaving some seedheads and stalks
Leaving the stalks and seedheads to stand through the winter provides essential food and cover for birds, mammals and insects that overwinter in our area, and has the added benefit of adding interest – or “winterest” – to your landscape. The varied textures and structure of an uncut landscape provide viewing pleasure through the cold months.
“If you choose not to cut things back and leave the seedheads, it’s great for wildlife,” says Susan Boss, a horticulturist at Mt. Cuba Center, “but be aware that the seeds you leave now could sprout in the spring.”
Shredding fallen leaves with a lawn mower or leaf shredder makes a nutrient-rich mulch.
2. Use leaves as mulch for added nutrients
Shredding the leaves with a mower or leaf shredder and returning them to the yard make nutrient-rich mulch. Some leaves, like those of tulip tree (Liriodendron tulipifera) will form a lawn-smothering mat when they fall to the ground. “You should get them up and get them shredded,” said Vic Piatt, Managing Horticulturist at Mt. Cuba Center, “they’re going to be a problem if you don’t.”
Oak leaves, on the other hand, curl and dry up where they land and take a long time to decompose, which makes them particularly useful in mulch. Simply rake them back into the garden bed or pile them into a leaf-only compost heap. After they slowly decompose over the winter, you will have a ready-to-use, nutrient-rich mulch in the spring.
Thoroughly water and cage young and small-diameter trees to protect them from deer who may browse or rub their antlers on them.
3. Edit and add new plants
Autumn is an opportunity to take a fresh look at the habitat you’ve nurtured all year and to reflect on what you would like to add to your garden. Consider filling empty spaces, or switching out a plant that isn’t thriving. “If you notice something that has beautiful fall color, or things that are doing well, or things that you want to divide, note it and work on that,” Boss said.
Maybe a large fothergilla (Fothergilla major), eye-catching with its glowing fall color, is something to add to next year’s garden. Or perhaps next year is the time to plant an oakleaf hydrangea (Hydrangea quercifolia) to bring its deep red autumn foliage into your yard. Note these and other colors you’d like to add to your autumn display, and plant them now, or once spring comes back around.
Pee Wee oakleaf hydrangea packs multi-season interest into a diminutive package – perfect for the front yard.
4. Protect new additions to the landscape
Frost makes planting at this time of year risky, but as long as the ground’s not frozen, fall can be a great time to add trees and woody shrubs to your garden. “You just have to make sure it’s well watered going into the winter,” says Boss. “That’s the key.”
The first watering after planting is a step that can’t be skipped, especially as the air turns cold. The water collapses air pockets in the soil around the planting, which is necessary for the health of the plant. “If you have an air pocket, that’s where roots will die,” Piatt said. “Roots need to be in contact with the soil.”After the tree or shrub is firmly in the soil, water the new plant thoroughly.
Make sure to put down plenty of mulch around the new plant in order to insulate and protect it against “heaving,” a process which can occur when the water in the soil freezes and forces a plant that isn’t rooted-in out of the ground and into the cold air.
Another note: Watch out for deer! In late autumn, bucks use trees to scrape the felt off their antlers – they especially love smaller trees because the trunks and branches can get between the tines on antlers. This is potentially deadly for the tree. Cage, stake or otherwise protect the smaller trees to protect them.
Fothergilla (both large and dwarf cultivars) provide a stunning show of autumn colors in the garden.