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Trimming Japanese Maple Trees

My split-leaf Japanese maple tree is 15 to 20 years old, about 7 feet high and about 10 feet wide. It is overtaking the corner of the yard. Can I trim it, and at what time of the year?

Trim your tree in late fall to early winter when the tree is dormant. Remove only one-third of the amount you want pruned each year, being careful to retain all its charm.

“Go easy on it,” says Joann Madon, horticulturist, The Growing Place, Aurora and Naperville.


Peony Blight

Last summer my neighbor told me the black spots on my peony were a blight, although my peonies bloomed nicely. What can I do about this?

Your peonies probably have a fungal disease, a common problem. The causes are wet summers with cool damp nights, too much shade, poorly drained soil, or a lack of air circulation. While your neighbor diagnosed your problem as peony blight, which is caused by an air-borne botrytis fungus, the black spots indicate the more common phytophthora blight, according to Walter Schmidtke, nursery manager at Pesche’s Garden Center in DesPlaines.

Early in the spring, young emerging shoots may suddenly wilt and fall over, turn black and show masses of gray-brown botrytis spores. If nothing is done, these spores are carried to developing buds, which turn black.

Black spots on foliage, leaves turning red in summer, and black stripes on the stalk indicate phytophthora. “Plants with these conditions won’t have as much zest” said Schmidtke.

The best protection against recurrence of either blight is good sanitation. In fall, it is important to cut down and throw away all peony foliage, cutting stalks just below the surface of the ground.

If this doesn"t work and you resort to chemicals, the treatment is the same for both diseases. As soon as the shoots emerge in spring, begin spraying with Mancozeb, a copper sulphate solution, and repeat every 7-10 days until buds form, according to University of Illinois Extension. Spray the whole soil area for overwintering spores. In early summer you can spray plants with Daconil, a general purpose fungicide. Cut away any diseased foliage at once.


Overwintering Marginal Plants

I keep seeing photos of interesting plants I’d like to grow, but they’re labeled zone 6 and I’m in zone 5. What can I do to successfully overwinter these marginal plants? I’d like to try them, but I don’t want to waste my money.

“Pushing a plant past the limits of its hardiness is not for the average gardener,” says Marie Dvorak of The Planter’s Palette in Winfield, “but plants can sometimes be successfully overwintered by siting them in a special microclimate such as a sheltered southern exposure.” Another tip comes from horticulturist Ann Hancock at Michigan State University, where they are trialing perennials that the English firm Blooms of Bressingham is introducing in the U.S. Hancock explains that the best way to keep perennials that are tender in Zone 5 or that are rated for Zone 6 is to grow them in raised beds with good drainage because poorly drained wet soils will cause the roots to rot. In addition, it is important to check perennial beds for plants that have heaved out of the soil through repeated freezing and thawing. Replace them in the soil and protect with mulch.

One example of a marginally hardy plant that will be getting attention this year is ‘Flamenco’, a new cultivar of Tritoma (Kniphofia, red-hot poker) that has just been named an All-America Selections Winner for 1999. Tritomas should have their foliage tied upright so water does not remain in the crown, said Hancock.


White Pine Trees

I have lost four 12-15 foot tall white pine trees over the last year. All had the same symptoms, browning needles at the bottom that continued up to the top. Can you tell me what pest is killing the white pines? I am also losing an Austrian pine now. It is experiencing the same symptoms.

White pines in this area are very rarely troubled by disease. They are, unfortunately, highly susceptible to high pH problems, or soil alkalinity, and are utterly intolerant of salt, according to Rich Eyre of Foxwillow Pines, Woodstock. The browning needles could also indicate the plant is getting too much water or has poor drainage.If environmental problems are not the issue for your white pines, consult an expert. Betty Lockwood, Plant Information Specialist at the Chicago Botanic Garden, suggested you bring them a sample branch to check on disease and bring in an arborist for an on site visit to check your growing conditions. Or take a 12-inch sample of an affected tree to your local extension office.Austrian pine is very tolerant of environmental conditions but is prone to certain diseases—diplodia tip blight and dothistroma needle blight, both caused by a fungus. Only an arborist or a laboratory can provide an accurate diagnosis. If you bring in a 12-inch sample for diagnosis, be sure to sterilize your pruning shears with denatured alcohol after cutting the diseased wood.


Pumpkins

I’d like to know the secret to growing a decent-sized pumpkin for jack-o-lanterns for the grandkids and for decorating. My experience in recent years is that they get about as big as a basketball and then begin to rot. What am I doing wrong?

The longer the fruit is on the vine, the greater the chance it will rot. By September its size is apparent, and it turns orange. It is best to plant pumpkins in different soil each year or every two years, according to Sue Murdock, manager, Goebbert’s Pumpkin Farm, South Barrington.

The size and use of pumpkins is determined by the seed you buy. ‘Atlantic Giant’ produces fruits that weigh hundreds of pounds. A better choice is to grow ‘Howden’. It bears well-shaped 10 to 20-pound fruits, the perfect size for jack-o-lanterns. ‘New England Pie’ is the standard for pies with smooth, bright orange flesh. ‘Wee-B-Little’ is a miniature round pumpkin bearing 3- to 4-inch fruit useful for table decorations and suitable for tiny hands.


Ground Cover Suggestions

I have a dampish area with poor grass and moss that I would like to change to ground cover, but if I have only one plant, won’t it be boring? Can I get rid of the grass in winter or early spring?

If we have a dry winter or spring, you can smother the grass with a heavy layer of newspapers held down by bricks or stones, or use a product that will kill the grass. Use it according to the label directions. Grass roots are very persistent, so you may have to dig out the remaining roots by hand. The moss will disappear as you aerate the soil and rake in organic material.

When your area is properly prepared, you will have a large choice of low-growing groundcovers.

Kim Schroeder, perennial buyer at Wasco Nursery and Garden Center, St. Charles, suggests the following: lily of the valley (Convallaria majalis), sweet woodruff (Galium odoratum), wild ginger (Asarum canadense), or European ginger (A. europaeum), vinca (Vinca minor), Tiarella, Astilbe-the cultivar ‘Perkio’ is shorter than Astilbe chinensis ‘Pumila’ and violas such as bird’s foot viola (Viola pedata) or sweet white viola (V. blanda).

These choices are not aggressive growers like goutweed (Aegopodium), which grows anywhere and is very difficult to eradicate. You can plant free form areas with one type and another alongside it as contrast. Most of these ground covers bloom at slightly different times to give you a spring-into-summer flowering season.


Japanese Red Maple

I have a nicely sheltered, rounded 7-foot tall Japanese red maple on the southeast corner of my backyard. Half of the tree has lost its leaves, the formerly red bark is turning gray, and a good-sized square of bark has been stripped off on the side that faces the yard. I sprayed the exposed bark with black pruning spray to close any entry for insects. I have not cut off any of the branches.

Does the winter have any effect on the tree? Should I look for some insect infestation? What should I do now?

“It appears that the tree suffered some kind of injury. Over winter, watch for sun scald on the southern exposure. Use paper tree wrap on the trunk,” advises Mike Geimer, owner of Geimer Greenhouse, Long Grove. If you are fearful of insects, you can use an organic pyrethrum spray. Black pruning spray is not necessary.


Container Plants for Fall

Besides mums, what are a few other plants you would recommend for containers for fall color?

Jackie Weiss, garden center manager, Linton’s Enchanted Gardens, Elkhart, Ind.

Dwarf or miniature sunflowers add a bright, sunny pop of color to any container. Mix them with pink celosia, ornamental kale, dwarf ornamental grass and ornamental peppers for a special autumn arrangement. The kale is a great addition as the colors get brighter with colder temperatures. Ornamental pepper can also be taken in and kept as a houseplant through the winter months. Or use aster through October and plant in the garden before the soil freezes. Comes in many colors.

Tracy Bordis, product line specialist, Lurvey Garden Center, Des Plaines, Ill.

The rudbeckias ‘Indian Summer’, ‘Prairie Sun’ and ‘Becky Cinnamon Bicolor’ all have beautiful large flowers. Herbs and leafy vegetables like Swiss chard ‘Bright Lights’, mustard ‘Red Giant’, bronze-leaved fennel and variegated sage all add fun textures. Plectranthus ‘Mona Lavender’ combines nicely with ornamental kale and cabbage. Also plant trailing pansies like those in the ‘Cool Wave’ series at the edge of planters and hanging baskets. Another creative way to add interest to fall planters is with preserved and dried botanicals, sticks or accents.

Zannah Crowe, horticulturist, Monches Farm, Colgate, Wisc.

Our favorite addition to autumn containers – hands down – is ornamental kale. As the temperatures drop, the leaf color intensifies and the plant actually becomes more attractive. We frequently pair ornamental kale with late season grasses as well as decorative gourds and squash tucked amongst the foliage to celebrate the abundance of the harvest season. Your visitors may still be enjoying your kale peeking through the early snow on Thanksgiving Day!


Japanese Maple

I’m moving to a townhouse with limited direct sunlight. I would like to put a Japanese maple in a north-facing garden but don’t know if it will do well. What are the best kinds? Also, when is the best time to plant a small tree?

Japanese maples are small decorative trees which are becoming more popular as more dependable cultivars come on the market. Even so, an established tree will sometimes succumb in a severe winter. Their light requirements vary.

The trees can grow in a northeast exposure, and 6 hours of sunlight is not too much, according to Jeff Sibley, nursery manager of Red’s Garden Center, Northbrook. They need a moist, well drained, neutral soil, amended with organic matter. They can grow to 8 feet tall in a good location. He says the best planting time is right after Mother’s Day. A protected spot and plenty of moisture are critical elements for survival, even with the newer cultivars.

Sibley recommended the following cultivars of Acer palmatum var. dissectum, a cut-leaf variety, as the most graceful trees:

  • ‘Crimson Queen’ is a small shrubby tree, with finely cut reddish leaves that hold color all summer and turn scarlet before dropping off in the fall.‘Garnet’ is similar to ‘Crimson Queen’ but a somewhat more vigorous grower.‘Bloodgood’ is a vigorous, upright tree with blackish red bark. It has deep red spring and summer foliage, scarlet in the fall.
  • Acer palmatum var. dissectum ‘Viridis’ Lace Leaf Japanese Maple is a small shrub with drooping branches, green bark and pale green, finely divided leaves that turn gold in autumn. It takes shade.

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questions

I have a Japanese maple that was hit by frost. Some of the leaves are curled and brown. Will they fall off and new leaves grow? Is there anything I can do to help the tree? What is the best method to prevent this from ever happening again?

From what I have read, hellebores are supposed to spread. I have a few I planted four years ago, and they seem to be the same as when I planted them. They are planted in a bed of vinca. Should I remove more vinca that surrounds them? I do fertilize them and protect them with a winter mulch. What else should I be doing to have more plants?

I brought a frangipani (Plumeria) back from Hawaii last April when it was just a leafless branch. It sprouted leaves and grew over summer. Now it is losing its leaves. How can I keep it growing over winter? Will it bloom?

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