Japanese
Maple
Q: 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?
A: 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.
Trimming Japanese Maple Trees
Q. 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?
A. 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. Back to top
White
Pine Trees
Q: 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.
A: 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.
White Pine Burn
Q. I have two 20-year-old pine trees whose needles are turning brown on the west side of the plants. On the east side I have a compost pile.
I live in the St. Charles region and my soil is mostly clay. What is causing the browning? Should I get rid of the compost? How do I correct the damage?
A. Climate conditions could be the cause of the brown needles. There was strong west wind this past winter season, which caused winter burn. With last fall's rain and winter snow cover, the soil never dried out. According to Todd Mohr, sales associate, Rich's Foxwillow Pines Nursery, Woodstock, pines normally begin
to go dormant in late August. "We
had a lot of burn on our evergreens which showed up over summer," says Mohr.
Cut a sample of the branch and make sure the plant is alive. You can photograph your tree or take the sample to an arboretum or garden center for evaluation. The compost should not affect the trees unless you have a large pile that is prohibiting air circulation. Spread the compost loosely over the area.
White pine is a native Illinois tree. It may come back on its own. If not, have a tree professional diagnose it. Back
to top
Large Tree Replacement
Q. What is the largest tree that one can plant? We are trying to replace some 7- to 8-foot trees that were recently destroyed.
A. Trees sold at garden centers that are 2.5 to 3 feet tall, with a 2.5 inch diameter trunk, can be planted by hand. A hole for a 'balled and burlap' tree with a 5 to 6-inch diameter trunk can be dug by hand without a tree spade.
Any tree with a trunk larger than 6 inches in diameter would need a tree spade to do the moving and digging. Even large trees, such as a 35-foot tall tree with a trunk 9 or 10 inches in diameter can be transplanted with proper equipment. "Spruces 30 feet tall can be installed easily with a tree spade," according to Greg Oltman, owner, Gro Horticultural Enterprises, Huntley. Back to top
Birch Trees
Q. I'd like to plant a white bark birch in front of my home in my sunny front yard. What can you tell me about Betula utilis var. Jacquemontii?
A. The birch, Betula utilis var. Jacquemontii is a tall, narrow tree (to 100 feet) with very white bark that's native to India. It is subject to borers. The popular weeping white bark birch, B. pendula is also subject to borers in our climate and is not a suitable choice.
"There are better birch choices, so choose what grows well in our area," advises Ken Morris, vice president
of Spring Bluff Nursery in Sugar Grove. Two trees resistant to borers are the paper or canoe birch and
the river birch.
Canoe or paper birch (B. papyrifera) has a stout trunk with creamy white bark that peels off in papery layers. It is native to North America. It is the first paper birch bred to resist the bronze birch borer, but it still needs to be monitored and sprayed yearly for the borers. A good cultivar is 'Renaissance Reflection.'
River birch (B. nigra), native to the eastern United States, is fast growing when young. It can reach more than 50 feet in height. Its bark is a smooth, shiny apricot and, when mature, flakes and curls in cinnamon strips. It tolerates slow drainage and is also resistant to borers. "It's pretty tough, good and sturdy," says Morris.
The cultivar 'Heritage' was
introduced to much acclaim around 15 years ago.
Birch trees need moisture. Do not allow your tree to dry out in your sunny site. Back to top
Tree Planting
Q. What is the best time to plant a tree in northern Illinois?
A. The two best times to plant a tree are April-May or September-October because the weather is cool and there is a good moisture supply, according to Joni Cotten, nursery stock manager, Hawthorn Gardens in Hawthorn Woods. However, planting times can vary, depending on the plant and its method of growth.
Bare-root trees are planted when dormant. They are less expensive, and the planting hole can be back-filled with soil dug from the hole. Trees that have burlap-covered root balls are generally planted in the cooler months, while trees in containers can be planted at any time. Rhododendrons and evergreens are not planted bare root.
"Birches and oaks are dug in nursery fields and planted in the spring. Oaks especially have a long tap root, so they do best when they have the entire season to grow," says Cotten. Back to top
Tree Position
Q. What is the correct distance from my house to plant a tree? What is the correct distance from the lot line to plant a tree?
A. It depends on the size of the tree you are planting. A small tree such as a serviceberry (Amelanchier) or a dwarf flowering crab could be planted as close as four to five feet from
the house. For
a birch tree,
a distance of six to eight feet would be the minimum.
Distance from the lot line does not matter as long as it doesn't interfere with power or sewer lines. You should check with your village before planting. Closeness to the neighbor's lot line is not an issue, because neighbors have the right to trim back any overhanging branches, according to Matt Zerby, partner in Wasco Nursery, St. Charles. Back to top
Pines in Winter
Q. This past spring I planted a lacebark pine (Pinus bungeana) in full sun. As winter began, the angle of the sun's rays has caused the tree to receive, at most, 4 hours of sun. What are sun requirements of evergreens in winter?
A. In general, pines adapt to the winter weather by becoming dormant, says Susan Eyre, Rich's Foxwillow Pines Nursery, Woodstock. It is the freeze and thaw cycle that is hard on a plant, not the loss of sun hours. In a January thaw, sap rises and then freezes, which can cause the bark to crack, but plants usually recover.
Italian Cypress
Q. Is it possible to plant and grow Italian cypress in the Chicago area? Are our winters too severe for it? If they are, is there an alternative conifer that will provide a similar look?
A. Italian cypress (Cupressus sempervirens) has dark green foliage and horizontal branches and grows into a dense column 60 feet high in Italy. It is not hardy here.
Paul Jeffers, tree and shrub salesperson, Gethsemane Garden Center, Chicago, suggests substituting a dense, columnar arborvitae, (Thuja occidentalis 'Fastigiata'). It grows to 25 feet tall and 5 feet wide, but can be kept lower by pruning. The very narrow arborvitae 'DeGroots Spire' is another choice. The false cypress Chamaecyparis nootkatensis 'Green Arrow', often mistaken for arborvitae, is a tight upright growing plant. Back to top
Colorful Shrubs
Q. I am interested in improving fall color in my yard. What shrubs turns red beside burning bush (Euonymus alatus)?
A. Wendy Vichitk, plant manager
at Luurs Garden and Flower Shop, Hillside, recommends these shrubs
for a colorful fall garden:
Low growing 2- to 3-foot Virginia sweetspire 'Little Henry' (Itea virginica) has red foliage and grows in both
sun and shade. The foliage of the somewhat taller 'Henry's Garnet'
is dark red, as the name indicates.
Fothergilla 'Mount Airy' has blue-green leaves that turn intense yellow and orange-red in sun and half shade.
Oak leaf hydrangea (Hydrangea quercifolia) grows in shade or partial sun, with orange-red to red fall color.
The leaves of apple serviceberry (Amelanchier grandiflora) burn a bright orange red. There are several cultivars
on the market to choose from.
Many viburnums have bright fall color. The easy to grow Korean spice viburnum (Viburnum
carlesii) and the also fragrant V. juddii have leaves that produce a mixture of red, orange and mahogany. Arrowood viburnum (V. dentatum) and cranberry bush viburnum (V. trilobum) both exhibit typical red-purple color.
The intensity of color is affected
by the weather. Warm sunny days
followed by cool nights bring the highest leaf color. The health of the plant, its growing conditions, and the amount of water the plant receives also affect fall color. Back to top
Heptacodium
Q. Late last year most of the leaves on my year-old seven-son tree (Heptacodium) turned brown, starting at the tips. It had some new growth on the tips and buds. I used a tree ring soaker hose every two weeks.
A. "I suspect that your watering every two weeks was not sufficient and that your tree was going into early dormancy," says Chicagoland Gardening editor Carolyn Ulrich. "It was very dry late in the growing season and a lot of trees looked stressed."
A rule of thumb for watering is one inch per week. Heptacodiums grow best in moist soil. You probably needed to increase the amount of time the water was on the plant and also water more frequently. Soaker hoses can run for hours.
If you want to figure out how much water your tree is receiving, use a sprinkler, if you have one, and run it on your tree until a tuna fish can has an inch of water in it, and then stop. Do this weekly, unless it rains. Back to top
