Dear Master Gardener: Rose chafers have eaten all the blooms from my roses and peonies. Although I don’t like using insecticides, is there one I can use to get rid of them?
Answer: Rose chafers are found throughout Minnesota, especially in areas with sandy soils, such as ours. They feed on the foliage of many plants, but primarily feed on the blossoms of roses and peonies. If you have large numbers of rose chafers, you can treat plants with a garden pesticide. More applications may be necessary when they are numerous. Look for a pesticide that has bifenthrin, esfenvalerate, cyfluthrin, imidacloprid, permethrin or carbaryl as an active ingredient. The non-toxic, tedious method is to pick them off and toss them in a bucket of soapy water. The good news is — rose chafers are usually done feeding around the end of June.
Dear Master Gardener: My sister in southern Minnesota has a Mockorange. Can we grow them up in zone 3?
Answer: Mockorange (Philadelphus) is a lovely, white-flowering shrub with a fragrance reminiscent of orange blossoms. When it’s in bloom it is gorgeous, but the rest of the year it has little to offer. Blizzard is a cultivar hardy to zone 3. At maturity it will get 5 feet tall by 3 feet wide. Plant it in full sun to light shade — you will have the best flowering in full sun. It will need occasional pruning to maintain an attractive shape. Like all other spring blooming shrubs, prune it immediately after it’s done flowering.
Dear Master Gardener: I have a small orchid and the leaves are limp and wrinkled. What’s wrong with it and will it recover?
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Answer: Limp, wrinkled orchid leaves are typically due to over or under-watering. If you pull the plant out of the container and the roots are mushy and soggy, you have over-watered it. If the roots are dry or shriveled the plant is under-watered. If the orchid has been over-watered and the roots are mushy it may be too late to save it, but you could let it dry out, trim off the mushiest roots and give it a try. If it has been under-watered, it can probably be saved by rehydrating it and watering it correctly moving forward. Orchids should be watered well and then allowed to dry out slightly between watering sessions. Don’t use ice cubes! They are susceptible to root rot and death when watered too frequently.
Dear Master Gardener: Is trumpet vine a good choice for our pergola?
Answer: Trumpet vine (Campsis radicans) is hardy in zones 4-8. If you are going to try growing it in zone 3 plant it in a sheltered site and give it some winter protection. Its large flowers are quite spectacular and bloom over a long period. Hummingbirds pollinate them by day and sphinx moths pollinate them at night. After flowering, long, bean-shaped pods are produced that often continue into winter. Trumpet vine grows in full to part sun, but will flower best in full sun. It is a vine that grows vigorously and climbs by both aerial roots and twining. Keep in mind — it may take a few years after planting before it flowers. Trumpet vine suckers and reseeds freely, so keep it in check with timely removal of suckers and pulling up seedlings as they appear. Flowers range in color from red, orange and yellow. Minnesota Red Trumpet Vine is a red cultivar that grows 25-30 feet tall and 5-6 feet wide. Yes, a pergola is a good choice because this vine needs substantial support.
Dear Master Gardener: I would like to purchase a bird bath for my garden and was wondering if some are better than others. Should placement be a consideration?
Answer: Providing water for birds can improve the quality of your backyard bird habitat and give you an excellent opportunity for bird-watching. Not only do birds need water to survive, they also use water for bathing, cleaning their feathers and removing parasites. The typical bird bath sold in lawn and garden shops (picture a concrete basin mounted on a pedestal) make nice lawn ornaments, but are not necessarily what is best for most birds. First, they tend to be too deep. Second, they can be hard to clean. Third, they can crack if left out during the winter.
When you choose a birdbath, look for one made of tough plastic that can be cleaned easily and won’t break if the water freezes. A birdbath with a gentle slope allows birds to wade into the water. If you want to make your own, you can use a garbage can lid, saucer-style sled or even an old frying pan. The goal is to try to imitate a natural puddle as much as possible. Birds seem to prefer baths at ground level; however, if there are cats around, raise the bath 2-3 feet from the ground. To give birds footing, place sand in the bottom of the bath. If your birdbath is on the ground, you could place a few branches or stones so that they stick out of the water; then birds can stand on them and drink without getting wet (especially in the winter). The best place to put your birdbath is in the shade near trees or shrubs. The shade will keep the water fresh longer and slow down evaporation. The trees or shrubs will provide nearby cover from predators. To really make your bath attractive to birds, provide moving water. You can purchase products that drip or spray water into a birdbath. Keeping your bird bath full of clean water at all times is the key to attracting a large number of birds to your yard. It is important to clean it every few days with a weak vinegar solution (never soaps or detergents) and clean it immediately if you see algae starting to form.
You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at umnmastergardener@gmail.com and I will answer you in the column if space allows.
University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.
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