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Leaf cut-outs from beneficial insect won't harm rosebush

The circular cutouts on these rose bush leaves are made by leafcutter bees, which use them for nesting material. Special to Forum News Service 1 / 2
Don Kinzler, gardening columnist 2 / 2

Q: I never see any insects on my rose bushes, but find damage to the leaves as pictured, with neat circular cut-outs. I've tried a systemic insecticide, and it doesn't deter whatever is munching on the leaves. Do you know what might be doing this damage? - BeAnn Canton, West Fargo.

A: The circular cutouts are made by leafcutter bees and are very common on rose bushes. The bees don't eat the cut leaf sections, but use them for nesting material. Because they don't consume the leaves, just cut through them, insecticides aren't effective.

Leafcutter bees don't harm the rose bush, other than making the leaves slightly less attractive. Because they are important pollinators, eliminating the bees isn't recommended. Leafcutter bees are about the size of honeybees, but they're loners, not living in colonies or group hives. They also aren't aggressive and are quite shy, which is why they're rarely seen, leading to the common question about what's causing the neat holes in rose leaves.

Q: I'm looking for shrubs to grow as a hedge. The soil is good quality and the area is sheltered by trees. Boxwood would be interesting, but I know hardiness is our problem. Your opinion would be appreciated. - Tom Olson, Jamestown, ND.

A: You're right about the boxwood, whose small, oval leaves remaining green year around classify it as a broadleaf evergreen. It makes a neat little hedge in very protected areas, but isn't suitable for standard yard hedges in our area.

The University of Minnesota Landscape Arboretum has about 75 different shrub types grown as hedges, which demonstrates that most shrubs, if planted closely in a row, can make a hedge. For trimmed hedges, shrub types with smaller leaves are best, because they shear more cleanly. For untrimmed natural hedges, choose shrubs that mature at the height desired.

Common hedge choices include alpine currant, dwarf Korean lilac, ninebark, spirea, barberry, aronia, diervilla, dogwood, caragana, juniper and arborvitae. Cotoneaster was once the leading hedge type, but it's susceptibility to fireblight diminished its popularity, although it still makes a nice hedge and can be rejuvenated if problems occur.

Q: On the corner of my property stands the old village well, with the old pump still in place. I'd like to plant Wilton Carpet junipers around it to dress it up a bit, and because they only grow five or six inches high while spreading eight to 10 feet, they'd be perfect. When is the best time to plant the bushes? Am I too late to do it this year? Regina Messmer, Bordulac, ND.

A: Wilton Carpet or similar varieties of low-growing creeping Juniper would make a nice addition to a neat old feature. Potted nursery stock can be planted all season with good success. Monitoring for water is important, the same as it is for material planted earlier in the season. Water very thoroughly immediately after planting. Check moisture situation daily. Daily watering may or may not be needed. Monitor by scraping aside a little soil over the rootball. If moisture is visible close to the surface, don't water, but if the rootball is dry, soak thoroughly. Wood mulch greatly reduces moisture lost to evaporation.

If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.

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