Dear Master Gardener: I’ve heard that blue false indigo is a deer and rabbit resistant plant. Does it grow in this area?
Answer: Baptisia, false indigo, is an easy to grow, low-maintenance, long-lived perennial that is hardy to zone 3. At maturity a Baptisia gets about 3-4 feet in height and width, but it can take a year or two to become an established, flowering plant. They develop an extensive, deep root system and should not be disturbed once established. Baptisia are members of the legume, or pea family and have the capability of fixing nitrogen in the soil. Plant them in deep, rich soil that drains well and add lots of organic material to the soil. A Baptisia blooms for several weeks in May to June and grows best in full sun, but can tolerate light shade. Their black seed pods are valued additions to dried flower arrangements. These plants have no serious insect or disease problems, are a non-preferred plant for rabbits and deer, and attract butterflies. Baptisia australis, blue false indigo, forms a mound of bluish green foliage and blooms with spikes of one-inch blue flowers. There are many new cultivars on the market. Purple Smoke has gray-green stems with purple-blue flowers that look gorgeous at peak bloom. Carolina Moonlight has spires of soft, butter yellow, pea-like blooms with blue-green foliage. Baptisia can act as a shrub, or make an excellent addition to a perennial border or cottage garden.
Dear Master Gardener: When my ivy is outdoors it is dark green. Why is it lighter in the house?
Answer: Light levels will affect the color of your ivy. Outdoors, English ivy does best in shade to part shade, which could lead a person to think they are a low-light houseplant. However, grown indoors, most ivy cultivars grow best in medium to bright light, but not direct sunlight. The variegated cultivars benefit from medium light and the solid green ones typically prefer brighter light. Ivies tolerate low to medium light but growth will be reduced, their leaf color will dull, and variegated forms may turn all green.
Dear Master Gardener: My lilac bush is growing in full sun, but last year had fewer blooms than previous years. Why?
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Answer: Typically, when a lilac bush produces fewer blooms, it is due to a decrease in sunlight. For example, another tree may have gotten larger and be blocking sunlight. Lilacs need a minimum of six hours of direct sunlight. Yours is growing in full sun, so that reason can be ruled out. Another reason lilacs might bloom less is due to overfertilization. If a lilac bush is planted in or around grass and the grass is being fertilized, then it could be getting too much nitrogen. Heavy fertilization, especially nitrogen, may promote lush foliage and inhibit flowering. As a general rule, it is not necessary to fertilize lilacs. If you are going to fertilize your lilac, do it very lightly in the spring. Pruning at the wrong time will also affect flowering. Lilacs bloom on the previous year’s growth. It is important to prune them immediately after flowering. If you prune them too late in the season you may be removing flower buds.
Dear Master Gardener: I would like to plant a Japanese tree lilac this year. Isn’t there a Chinese tree lilac too?
Answer: People seem to be longing for spring! Yes, there are both Japanese and Chinese tree lilacs and they are closely related. The Japanese tree lilac (Syringa reticulata) is an upright, spreading, multi-stemmed tree. It blooms early in the summer with large hydrangea-like clusters of cream-colored flowers. The flowers have a honey-like fragrance. Depending on the cultivar, a mature Japanese tree lilac will reach 20-25 feet in height and about 15 feet in width. Snowdance is very cold hardy and has a more reliable bloom each year than the others.
The Chinese, or Peking, tree lilac (Syringa pekinensis) has smaller leaves and stems, smaller flowers, and more interesting bark than the Japanese tree lilac. It is an upright, multi-stemmed tree with showy, lightly fragrant, cream-colored flowers. This lilac has fascinating bark that peels and curls and ranges in color from golden to reddish brown. The two cultivars hardy to zone 3 are Copper Curls and Summer Charm. Both get about 20 feet in width at maturity, but Copper Curls gets 20 feet in height and Summer Charm gets 30 feet in height. Summer Charm has larger flower clusters than the rest of the species. All Chinese tree lilacs have seed heads that are eye-catching as they sway in even the slightest autumn breeze.
Dear Master Gardener: We have some property further north and when I was there the last time, I noticed some of the Norway pines I planted 10 years ago have been stripped of bark. I’m quite sure porcupines caused the damage. Will this damage cause the trees to die?
Answer: The porcupine, a common resident of the coniferous forests in northern North America, is an herbivore who feeds during the winter on the bark of conifers and hardwood trees. In the summer their diet mostly consists of plants found on the forest floor. Some of their favorite hardwood trees are maples, basswood, and elms. Their preferred conifers are white pine, jack pine and Scotch pine, but they are also known to eat the bark of Norway pine. Porcupine damage is more common in winter and on young trees with thinner bark and sometimes causes the decline or mortality of trees. During the winter, porcupines feed on tree bark and the tender branches in the upper part of the canopy. Squirrels can also cause damage by removing the bark from trees, usually in the upper canopy, but you will be able to tell the difference because the teeth marks made by porcupines are larger than squirrels, the marks go deeper into the wood, and the damage is more extensive. Telltale signs that porcupines are the culprit are clipped twigs on the snow, higher branches snipped off with clean slanted cuts, porcupine tracks, and/or bark chewed or removed on the trunk and branches at any level. Trees are frequently deformed from partial girdling, which exposes the tree sapwood to attack by disease, insects and birds. Bark plays an important role in protecting a tree by holding moisture and nutrients in and keeping disease and insects out.
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.
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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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