Rosemary McCreary: Time for cleanup in the garden

Autumn wind storms can easily wreak havoc on the garden, dropping leaves galore, bent and broken flower stems, twigs and branchlets. It can be a huge mess, but all of this debris is fodder for the compost pile. If the clean-up isn’t too onerous, we could thank the wind for depositing resources so close to home.

It might seem a bit of a stretch to think of garden debris as a resource, but for dedicated composters, this is valuable raw material for improving next year’s soil. Leaves and soft trimmings from perennials will break down over the coming months, many without much chopping to make the pieces smaller. Adding kitchen scraps and turning the pile every week or so will help keep it hot and hasten decomposition. If fall rains are less than adequate, water from a hose will keep the pile moist.

As you gather together dead and dying annuals and perennials, remember to leave seed heads for foraging birds. Year-round residents are always hungry and the migrants need nourishment for long journeys. I’m always amazed to find birds feeding where I least expect.

If you come across interesting branchlets with unusual shapes, colorful lichen, or other promising dried materials, set them aside to use in holiday arrangements. So many throw-aways from the garden transform themselves on a tabletop when we add a few fresh flowers or pieces of fruit.

LOOK FOR LAVENDER BUDS

As you cut back lavenders, shake the last of the seeds out of flower heads before tossing them into the compost. Hold stems a few at a time over a brown grocery bag to knock off seeds; then, transfer seeds to a smaller paper or cloth bag for freshening dresser drawers and linen closets.

Pruning lavenders is problematic for many gardeners, but it needn’t be. The goal is to achieve a pleasing form that can be maintained year after year. This shrubby perennial is most attractive its first season or two in the ground. As it ages, though, lavender can become leggy with exposed woody stems and tangles of twigs at the bottom.

Awkward shapes and legginess can be avoided by pruning plants after bloom once or twice each year, depending on the species. It often takes multiple trimmings to develop a consistently low, rounded outline or other pleasing shape.

The key is to refrain from pruning too lightly or too drastically, that is, cutting low on the plant but never too low, always above green branchlets or green buds. Plants are unlikely to survive a pruning into woody stems where there are no obvious buds showing. If more pruning is needed, look for new buds to appear in another few months.

INVASION ALERT

One of the most frustrating things we do as gardeners is cause our own problems. We all do it, sometimes consciously, sometimes not. Planting the wrong plant in the wrong place probably tops the list, but unwittingly promoting invasive plants in our own garden beds may be the most difficult to correct.

As we’re cleaning up the garden, it pays to watch for plants that will cause trouble. Here are some of the biggest headaches.

Bermuda grass (Cynodon dactylon). This tough grass for playing fields also makes a good lawn in warm, dry climates, but it spreads relentlessly from deep roots, underground stems (rhizomes), and creeping above-ground stems (stolons).

If you inherited this grass — few serious gardeners would ever plant it locally — the best you can do is to continuously pull it out of planting beds. Never put it in a compost pile.

Ivy (Hedera). In containers, ivy is well-behaved, but in the ground it escapes and becomes invasive when stems take root and birds distribute seeds. To remove it, dig out roots and remove subsequent leafy growth until plants die completely. Never put ivy in a compost pile unless you know it gets hot enough to destroy the plant.

Nut grass (Cyperus rotundus). This pest relative of the more friendly papyrus shows up in moist spots, often in lawns. Birds disperse seeds and once in a while a plant arrives in a nursery can. It’s difficult to eradicate because of tenacious underground tubers and nutlets that detach when the weed is pulled.

Look for grasslike leaves with 3-sided angled stems and a spiky tuft of flowers that sit above a leaf cluster. Remove such a plant when you first notice it and never put it in compost.

Ribbon grass (Phalaris). This very handsome variegated grass is so tempting in a nursery can that it’s hard to resist. I must confess that, fully aware of its aggressiveness, I once thought I could keep it under control in a container. It did stay in the pot, but in a matter of weeks completely overran its companions. Avoid ever planting ribbon grass in the ground. Compost it only in a hot pile.