Pruning, Japanese maples create questions
Q:
Recently, you mentioned pruning out one fourth of the oldest branches on spring blooming plants like lilacs. How should I properly prune summer bloomers like spirea, potentilla or crape myrtle?
A:
Small blooming shrubs like these can be planted for several different effects. They can be used as small specimens in flowerbeds, as low hedges, or multiple plants can be used together to create a mass effect. Each use of the planting methods can mean a different pruning technique.
Summer blooming shrubs can bloom on the ends of completely new growth that come up from the ground or base of the plant in the spring, or on the ends of short branches that grow off long branches left from the previous year. Some plants will do both.
Watch the plant when it blooms to see if it does only one way or both ways at the same time. If it only blooms on the ends of the new growth, then you can cut it down to the ground each year so that everything on the plant is new growth. This is usually done during the dormant season. If it only blooms on side branches of existing wood, you must leave some older branches until the next year. Branches that are three or four years old can be cut off at ground level to keep the plant young and blooming its best on young wood.
If it is a combination bloomer you can use either method to prune it, but you may lose some blooms by not leaving the proper amount of young or old wood. Only time will tell.
If the plant is being used as a hedge, use plants that bloom on existing wood, since you will always have existing wood. Prune after it is done blooming so you will not cut off the flower buds prematurely while trimming.
If the shrubs are planted in groups, they were intended to be a single unit. Pruning individual plants will ruin the intended look, and taking out one-fourth of the older growth may be difficult. They should be pruned as one or they should be cut down to the ground at the same time.
Unfortunately, it is difficult to tell you species by species, which plants to prune which way. I cannot list every species all over the country, and many species mix things up. For example, climbing roses flower on two-yearold wood while hybrid tea roses bloom on the ends of new growth.
Q:
We want to get a fern-leafed Japanese maple, but we have heavy clay soil. How should we plant it in this soil?
A:
There are many varieties of Japanese maples. Some grow 15 to 20 feet tall, while many of the cut-leaf or fern-leafed varieties are more shrublike and may stay only 3 to 5 feet tall.
Japanese maples can grow in clay soil to sandy soil, but they don’t do well in waterlogged soil. As long as the water drains away from the root area and doesn’t stay puddled in that area, the tree should do fine in your clay soil. If the area stays too wet, small Japanese maples can be planted in raised beds. Larger trees will grow bigger root systems that would be better off in the landscape and not in a root-restricting bed. They can grow well in acidic soil with azaleas, camellias and rhododendrons. If you want to add some composted organic matter to the area, the roots growing in that will be fine.
The entire area under the branches should be mulched. Do not grow grass under the tree. Japanese maples in hot summer areas do best in the shade of other trees or buildings, especially afternoon shade. In cool or northern areas, they can grow in full-sun areas.