Go ahead and lop the top

Q: I have a Japanese maple that is getting too tall for its spot. I like the tree but need it to be more compact. Can I cut off the top to keep it short?

-- Gail Simpson, Norcross

A: If you are prepared to maintain the tree a bit each year, you can remove the top. Gardeners in Europe have managed their trees in this way for centuries. The process is called "pollarding." Make your pruning cut just above an existing horizontal branch. Each year thereafter, remove the sprouts that arise below the pruned area. Consider tip pruning each of the lower branches in March to make them sprout denser foliage. If ever you move from your home, leave detailed directions for the new gardeners so they can continue your work.

Match tiller to size of job

Q: You mentioned recently that you have a "little two-cycle tiller" that works well for you. I have been looking for a tiller for several months now and have been told that only an expensive 6-horsepower rear-tine tiller will cultivate clay. They are expensive, plus being big and heavy. I garden about 3/4 of an acre of land extensively. Like every gardener, I spend half of my time digging clay and amending the soil. Can you tell me how to choose a tiller?

-- Beth Greenberg, Dawsonville

A: I guess it's a matter of matching the tiller to the job, both now and in the future. I have an acre to care for but I only till beds of 50-100 square feet at a time. They are small enough that I can spade up an area, then use my lightweight two-cycle tiller to mix in my soil amendments.

If you commonly till 1,000- to 5,000-square-foot plots, you need a bigger tiller than mine. A friend has a self-propelled heavy-duty tiller that is a dream to use on hard ground. It creeps slowly forward as it churns the earth. Even so, the tines penetrate only 8 inches. You must also consider your physical strength. Big tillers are heavy. Wrestling them around a garden corner or into a shed can be a backbreaking chore.

In my opinion, it might be best to rent a big tiller once or twice a year to dig big bed areas. Keep a two-cycle tiller handy for day-to-day gardening.

Ryegrass-zoysia mix not good

Q: I have always wanted a green lawn in winter. How much will it hurt my zoysia lawn to overseed with ryegrass this winter?

-- Henry Harris, e-mail

A: Turf researcher Clint Waltz says there is no real reason or advantage to overseed warm-season turf. You will inevitably harm the permanent turf grass by planting ryegrass into it. Ryegrass competes for nutrients the lawn will need next spring. In addition, fertilizing the ryegrass may make the turf grass more easily winter-damaged. That said, Bermuda grass is the only warm-season grass that can usually overcome the stresses of overseeding. Zoysia grows too thickly to allow ryegrass seed to penetrate to the soil and germinate.