At the end of every winter, there are many shrubs growing along sidewalks that are dead and damaged either by salt, wind or dogs. Are there any shrubs that I can plant in these more exposed situations and expect them to survive?
Sharon Yiesla, plant knowledge specialist, The Morton Arboretum, Lisle
First, we need to note that there are some exposed areas where we just shouldn’t try to grow plants. There’s too much ice melt or salt, and dog urine is always a problem. Evergreens are also out. There’s nothing that will tolerate wind or salt. That said, there are some deciduous shrubs that can work. Hydrangea are now a huge group, Potentilla tolerates everything, and fragrant sumac (Rhus aromatica) can survive shopping center parking lots. Rose of Sharon (Hibiscus syriacus) is tough, but look for double-flowered cultivars so they don’t go to seed so fast.
Peter Moersch, owner, Stonewall Nursery, Oregon, Wisc.
I would advise looking for something on a standard. A standard is a genetically compatible rootstock which has had another plant grafted onto it. Standards are usually 24–48 inches tall and serve to “pick up” the grafted section off the ground and make it more visible. This certainly helps with snow load and keeping plants away from doggies.
Many dwarf conifers and deciduous materials are used as grafted standards. Some examples would be dwarf white pine (Pinus strobus ‘Horsford’), globular blue spruce (Picea pungens ‘St. Mary’s Broom’), and Siberian cypress (Microbiota decussata). Many dwarf Korean lilacs (Syringa spp.) and hydrangeas are also done on standards.
Scott Stringer, certified arborist, Bartlett Tree Experts, Chicago
Starting your planting project with a soil test can ensure your tree or shrub selection has the best chance of survival and can tolerate existing salt levels. Options for shrub planting with a tolerance to salt are Hydrangea, witch hazel (Hamamelis virginiana), Spiraea, serviceberry (Amelanchier canadensis), and rose of Sharon (Hibiscus syriacus). Options for trees are Japanese tree lilac (Syringa amurensis), swamp white oak (Quercus bicolor), and in wet areas, bald cypress (Taxodium distichum).
I have a large variegated sedum with pink flowers that I have had for years. I noticed that it has started to send up some all-green shoots. Why is it doing this and how can I keep my plant variegated?
All variegated plants contain a combination of green cells with chlorophyll and white tissue with no chlorophyll, which produces the green and white effect. Variegated plants are genetically unstable, so sometimes the tissues revert to all-green cells and send up solid green shoots from the base of the plant. Because these shoots contain more chlorophyll than the variegated tissue, they are more vigorous. Thus they can quickly overrun a plant, according to Hortech, a developer and grower of sedums.
Cut the green shoots off at the base of the plant as soon as you see them. It is possible you have induced vigorous growth by giving the plant too much high-nitrogen fertilizer, so it would be wise not to fertilize. It sometimes helps to divide your plant and then choose the most variegated stems for a new plant. Since your sedum, a cultivar of Sedum spectabile, is such a rapid grower, it will quickly become a new clump after division. Newer named cultivars are more genetically stable and do not have this problem.
I have a cycas palm and am not sure how much direct sunlight or water it needs. It has light brown marks developing on the leaves. What is causing this, and how do I care for my plant?
Cycas palms or sago palms (Cycas revoluta) are tough house or patio plants. They are neither palms nor ferns but primitive cone-bearing relatives of conifers. A rosette of green feather-like leaves, 2 to 3 feet in height, grows from a central point at the top of a single trunk.
Cycas need bright light and should be kept relatively moist with weekly watering. However, prolonged rainy spells can cause fungal leaf spot disease.
“The shiny brown spots are probably caused by scale,” says Jeff Frohn, sales associate at Geimer Greenhouses, Long Grove. “It can be treated with fish oil, vegetable oil or an all-in-one insecticide spray,” adds Mike Geimer, owner, Geimer Greenhouses.
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.
What are the three best houseplants that everyone should own and why?
Bill Koch, owner, Hawthorn Gardens, Hawthorn Woods, Illinois
I tell people to go sit in Woodfield Mall and look at what’s doing well. We like to sell what will grow, what’s easy. So there’s ZZ plant (Zamioculcas zamifolia). It will survive if you go away for a 2-3 week vacation. Needs little water. Chinese evergreen (Aglaonema) is a wonderful plant. Will grow in any light; also doesn’t take much water. And pothos (Epipremnum aureum). We like to keep it simple.
Jackie Weiss, Garden Center Manager, Linton’s Enchanted Gardens, Elkhart, Indiana
Mother-in-law’s tongue (Sansevieria trifasciata) is one of the easiest plants to maintain. Find a place with dim light or low sun and forget it. The plant just needs a drink of water every 2-3 weeks.
Peace lily (Spathyphyllum). This is a phenomenal plant.Very easy to maintain. Will thrive in filtered sun but will do equally well in dim light. This plant loves moist soil.
Spider plant (Chlorophytum comosum) is a plant that keeps on giving. Very easy to take care of, it will often send out feelers with a baby spider plant attached. Just pop the baby in a pot of soil, allow roots to form and cut it free from the mother plant.
Dee Speaker, Greenhouse Manager, K & W Greenery, Janesville, Wisconsin
People think orchids are difficult to grow because they look exotic, but the Phalaenopsis orchid is easy to grow. The blooms are elegant and can last up to three months.
Spider plants (Chlorophytum comosum) adapt well to most places in your home and are one of the easiest plants there are. They are forgiving if neglected, and they also improve the air quality in your home.
FIddleleaf fig (Ficus lyrata) is a trendy plant. It’s easy to grow and adds character to a room. It can get tall but that’s what makes it blend in nicely with your décor.
Elizabeth Hoffman, Owner, West End Florist and Garden Center Evanston, Illinois
For high-light situations I like variegated Swedish ivy (Plectranthus madagascariensis). This trailing vine is so much fun with its vibrant white margin and aromatic scent. It prefers moist well-drained soil.
For medium light, I suggest mistletoe cactus (Rhipsalis pilocarpa). This is a cool trailing non-toxic succulent type plant that never likes to dry out. It is also not very sharp to the touch like other cacti. It prefer moist, well-drained soil.
For low light, I recommend snake plant (Sansevieria trifasciata). It’s very easy to care for as long as you let it slightly dry out between waterings. It’s very striking with its color and stiff upright habit.
I’d like to block an unattractive view of my neighbor’s house/yard. What are some good plant/tree choices to hide unattractive views?
I dislike staking perennials. Is there anything I can do to avoid it?
When is the best time to cut back hydrangeas? How far do I cut them back?