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.
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.
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?
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.
After a summer outside, my clivia has returned indoors. Last year it had only one puny flower. What treatment should I give it over winter to bring it into bloom?
A. Clivia miniata, sometimes known as Kaffir lily, a South African native, is a member of the amaryllis family. When growing clivia, it is important to observe seasonal changes. During short winter days, stop fertilizing entirely until spring, and stop watering also.
“Treat your plant like a cactus,” says Steve Butcher, tropical plant specialist at Sid’s Garden Center in Palos Hills. “You can keep it completely dry for a couple of weeks up to the point of shriveling before watering. Keep your plant in a cool place; 55 to 65 degrees is ideal, but that’s hard to achieve in many homes. It does not need a brightly lit location.”
When the days lengthen, move the plant into a brighter location and increase watering. There are no hard-and-fast rules on watering. The frequency depends on the pot size and the root mass. Use a water-soluble, high-phosphorus fertilizer every second or third watering. After you see buds, reduce fertilizer to once per month. Root bound plants flower better.
Following this regime last winter, Editor Carolyn Ulrich reported five bloom stalks on one of her plants in February. Other plants bloomed in March but one didn’t bloom until June. Clivia are considered a winter-flowering houseplant, but bloom time will vary. Be patient.
I plan on saving my amaryllis bulbs that I kept outside over summer, but I noticed red streaks on the inner side of the leaves. What caused that? Will I be able to save my bulbs?
There are several possible causes of red streaks in amaryllis hybrids (Hippeastrum), explains Bill Welter, owner of Victor Hlavacek Florist, Winnetk. If the streaks occur on the foliage only, excess moisture and not enough air around the bulb could have caused the streaks. Amaryllis is also susceptible to leaf scorch, which can cause red streaks on the foliage and on the bulb. This was common on older varieties.
You can save the bulb for next season by letting the leaves die down, then trimming off the foliage, and dipping the bulb in a fungicide solution. Another possible reason for leaf scorch is tobacco mosaic disease, transmitted by insects.
Would it help to apply a starter fertilizer on a poor green lawn in December? Will it give it a head start for spring? It hasn’t been reseeded.
Some people have applied fertilizer over snow when the grass is dormant. However, it is best to fertilize in November to winterize your lawn and give it a start for spring, according to Steve Hipenbecker, assistant manager of Nature Scape, Gurnee. Use a fertilizer labeled as a “winterizer,” not a “starter.” Lawn starter products, typically high in phosphorus, are intended for newly seeded lawns. Winterizer fertilizers are typically high in potassium, which helps increase cold tolerance and disease resistance. Although advertised for fall application, winterizer fertilizer can be applied in spring as well. You can seed in spring, but early September is generally considered the best time to seed a lawn. The soil is still warm, the nights have cooled down, and dew collects on the grass each morning.
What is the largest tree that one can plant? We are trying to replace some 7- to 8-foot trees that were recently destroyed.
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.
I am growing my potted tropical hibiscus indoors for the winter. The leaves are starting to yellow and fall off. Should I give the plant iron and should I fertilize it? Do I cut it back, and if so, when?
Hibiscus leaves turn yellow in response to the change in environment. The older leaves fall off first. If the leaves are chronically pale yellow with green veins, the plant could be lacking iron, but in your case, it is probably the change in growing conditions that is affecting the plant. When the days get longer in February or March, prune it to shape it, or cut it down to force good bottom growth.”
“Don’t panic; the plant expresses itself dramatically,” reassures Mike Geimer, owner of Geimer Greenhouses, Long Grove. “Don’t be timid pruning it.”
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?
Hellebores increase slowly into clumps so have patience, counsels Chris Darbo, wholesale manager of The Natural Garden, St. Charles, and an enthusiastic hellebore grower. “I have Helleborus foetidus, which has finely cut leaves and blooms in January, and H. orientalis, the Lenten rose. Both have increased in twelve years to four times the size of the original plants, but they haven"t self sown. They are planted in a bed of sweet woodruff in a partly shady location.”
“I also have a clump of H. orientalis that was transplanted into my back yard five years ago, and it seeds all over the place. It is planted in shade with no ground cover. My theory is if the seeds can"t reach the ground, they can"t grow!” It takes three years before seedlings bloom.
According to Darbo, hellebores do not need fertilizer. She never rakes leaves from garden beds but instead lets fallen leaves act as a winter mulch. Leaf decomposition over the years has helped her soil to become more loamy.
H. niger, the Christmas rose, does not self seed as readily as H. orientalis and H. foetidus.
Note: A new strain of H.orientalis has recently reached the market. Known as the Royal Heritage strain, it includes colors and patterns never seen before in the species. Fifteen years in the making, Royal Heritage hellebores were developed by John Elsley, Director of Horticulture at Song Sparrow Farm in Avalon, Wisconsin.
I have some peonies that I want to transplant but cannot plant them in their permanent place until next spring when our new house will be built. Can I dig them now and transplant them again next spring?
The correct time for transplanting herbaceous peonies is late September into October. Cut back the foliage when you dig them up. Each clump you move should have at least three eyes, or growth buds, and thick tuberous roots. Dig a hole deep enough to cover the eyes with two inches of soil when you transplant. If planted too deeply, they will not bloom.
Transplant the peony into its temporary place, or else move it into a container and dig the container into a shady area, not in full sun. Be careful about watering the container plant; try to keep it evenly moist. Next spring, move the peony into its permanent location, suggests David Leider, perennial grower at Klehm Plants, Barrington.
“Replanting in spring disrupts the roots and will halt blooming for one year. Peonies are pretty strong plants and very hardy. They will recover,” says Charlotte Thayer, assistant to the owner at The Natural Garden, St. Charles.
I start ‘Dragon Wing’ begonia from seed under grow lights. What other begonias can I use to cross-pollinate with the ‘Dragon Wing’ so I can collect my own seeds?
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?
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.