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?
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.
What are some trends in gardening you see becoming more prevalent in the next few years?
Current gardening trends continue to explore a variety of annual shade alternatives. Consider begonias of all types, such as fibrous, hiemalis, nonstop, rex, tuberous and the trademarked Big series and Dragon Wing. For a tropical feel, caladiums, elephant ears, and banana plants are not only exotic but add an element of height. Lastly, the hundreds of coleus varieties, along with black and chartreuse sweet potato vines, are colorful, reliable, and rich in texture.
I believe choosing plants for butterflies, bees and other pollinators will be an important trend in 2015 as folks realize the important role they play in our environment. Growing fruits and vegetables will also remain an important focus of gardeners, especially those that can be grown in containers and small spaces. Low-maintenance plants, preferred by both aging and beginning gardeners, will be another trend to watch in 2015.
People are looking for “bee-safe” plants that are free of neonicotinoids and other harsh pesticides. Also, they want to do vegetable gardening with non-GMO varieties. Succulents are very hot. The indoor use of succulents in dish gardens is a no-brainer; they look cool, they’re so easy to care for and make great unique gifts. Ornamental kale and cabbage have become very popular for fall decorating.
The popularity of hostas has made gardeners realize how much fun it is to use foliage for color, so they are looking beyond flowers to the reds and purples of coral bells (Heuchera); the yellow fall bottlebrushes of Amsonia hubrichtii; and the great fall colors of shrubs such as Viburnum, oakleaf hydrangeas (H. quercifolia), witch hazel (Hamamelis) and trees such as seven son flower, (Hepticodium), Ginkgo and scarlet oak (Quercus coccinea).
What causes black spots on my orchid leaves?
There are a number of causes for black spots, depending on the type of orchid.
“In some varieties, like Oncidium ‘Cherry Baby’, the small black spots through the leaf are normal,” says Liese Butler, owner, Oak Hill
Black spots on the top of the leaf could be sunburn, caused when sunlight scalds a drop of water that has been left on a leaf. Newer growth of Cattleya orchids can normally have a purplish spot. A black mushy spot and a black stem indicate rot.
What is rose rosette disease? I lost two antique roses and removed a hedge of multiflora roses that were supposed to be undesirable. How bad is it?
Rose rosette disease is a plant killer of unknown origin and no known cure. It is known to plant pathologists, but unknown to most rose gardeners in this area.
The disease is believed to be caused by a virus or virus-like pathogen that has been spreading through much of the wild rose population in the Midwest, probably transmitted by a mite introduced to the U. S. to eradicate multiflora roses. It is lethal to the wild multiflora rose and potentially lethal to many rose species and cultivars.
Symptoms of rose rosette disease are highly variable, depending on the species or cultivar. Some of the more recognizable symptoms include rapid elongation of new shoots forming witches brooms, or clustering of small branches with distorted leaves of conspicuous red pigmentation and distorted flowers.
David Robson, Springfield, extension educator, horticulture with the University of Illinois, reports that it is all over our area. Mike Geimer, owner of Geimer Greenhouse, Long Grove, reports coming across RRD in a Long Grove garden. One plant in a bed of Flower Carpet roses caught his eye because of its uncharacteristic red clumping stems. He looked up the symptoms on the internet, identified it as RRD and advised immediate removal of the plant. Also important, warns Geimer: “Always sterilize pruning shears.”
Kathy Hallgren, Sycamore, is worried about the future of old roses. Two summers ago she noticed some peculiarly rampant irregular, hyper-thorny pink growth with irregular leaves on an antique Alba rose.
After researching the symptoms, Hallgren determined the irregularities were from RRD. “I dug out the plant and burned it. Once I learned that multiflora roses could be the culprit, I removed them even though they were healthy. This summer I saw it on one of my ‘William Baffin’ roses so cut it down and burned it. This disease means business,” says Hallgren.
No effective control is available for existing rose rosette disease. All cultivated roses are potentially susceptible. Be on the lookout for it. Early detection is the key to effective cultural control. If the disease is recognized early and the rose is removed, it is possible to save other roses in the garden and hopefully curb the spread of RRD.
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?
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.
Now that bedding impatiens (I. walleriana) are not recommended because of impatiens downy mildew, what are three good annuals for shade?
Chris Williams, production manager, K&W Greenery, Janesville, Wisc.
I like New Guinea Impatiens. They make nice bushy plants that are full of large colorful flowers and are easy to grow. You also get a large color selection with New Guineas. The SunPatiens and Bounce impatiens are fairly new plants, and they are recommended for sun as well as shade. Then there’s coleus. Who doesn’t like its colorful foliage? Many varieties grow upright, but others also spread. Torenia, also known as wishbone flower, has trumpet-like flowers of white, yellow, rose and purple that cover nicely mounded, low-growing plants.
Karen Wedel, manager of the outdoor floral department, Wedel’s Nursery, Garden Center, Kalamazoo, Mich.
One of my favorites is begonia. Tuberous varieties have large colorful blooms; wax begonias are good for mass planting. I’m also a fan of the big leaf, 16-20 inch tall Whopper series with large waxy leaves and summer-long flowers.
Another idea is coleus and caladiums. They come in different foliage colors, work great in gardens and containers. They are both also easy-care.
Finally, torenia or wishbone flower, named for the small “wishbone” inside the mouth of the pink, yellow or blue-purple flowers. Blooms all summer. Some varieties will trail.
Kevin DeBoer, manager, Big John’s Farm Market and Greenhouse, Chicago Heights
My favorite is Dragon Wing begonias. They’re usually sold in 4½ inch pots or hanging baskets. At my house I removed them from the baskets, then planted them in the ground in full shade. They turned out awesome! Plain wax leaf begonias are also good.
In addition, I like coleus. They don’t produce flowers, but they have many different vibrant leaf colors. In full shade New Guinea Impatiens will flower sparingly, but if you put them in some sun, they will flower more.
I received a beautiful flowering azalea plant during the holidays. I would like to continue growing it over winter. Will I be able to bring it into bloom next year?
Trying to get azaleas to flower in the home is difficult and time consuming because the light in a house is lower than that in the greenhouse where it originated. But if you would like to try to keep your plant growing, follow these directions.
To keep an azalea flowering after you get it, give it water-soluble acid fertilizer at quarter-strength. Keep it in a cool, shaded location, away from heat-releasing light bulbs or hot air vents.
After flowering, remove the withered flowers and keep the plant in a cool, sunny location. Water as needed to keep from wilting. In summer, sink the pot in the garden in a semi-shaded spot. Water and fertilize regularly. Acid fertilizers will help to maintain proper soil pH and keep the foliage from yellowing. Before July 1, shape the plant if needed. Keep the plant outdoors as long as possible in the fall. The plant may need protection from early light frosts but should be brought in before heavy frosts or freezes occur.
Once the plant is indoors, place it in a cool area, 40-50 degrees. An unheated porch, cold frame or similar area is good. Flower buds develop during the cold period. About 6-8 weeks of cold are needed for bud development. Do not fertilize during this time and only water enough to keep the plant from wilting. Buds should develop and swell. In January, move the plant into a cool sunny area, about 60 degrees. Flowering should begin in a few weeks. If temperatures are excessively high during this period, buds often develop poorly and new shoots will grow right past the buds, hiding them. Additional humidity is helpful to keep the calyx on the flower moist and easier to open.
Even if your plant doesn’t rebloom, all is not lost. Azaleas are known to be air purifiers.
What trends do you see in container plantings, such as type of pot, materials, sun or shade, foliage or flowers.
Brenda Williams, Sales, Pesche’s Greenhouse, Floral & Gifts, Lake Geneva, Wisc.
As our lives get busier, gardeners are looking for easy care and double duty – plants with colorful or unique leaves. Like coleus.They come in all sizes from thrillers to fillers and even a spiller called ‘Rose Lava’ that tumbles over the edge. A tall nicotiana or canna lily easily substitutes for a spike in the center of a container. A euphorbia like ‘Diamond Frost’ might look delicate but is an excellent performer whose “flowers” are actually tiny white leaves.
I also see more succulent containers. With their diversity in texture, color and form plus low maintenance, they fit well in our busy lives. They are modern and bold.
Lori Harms, owner of Countryside Flower Shop, Nursery and Garden Center in Crystal Lake.
This year we saw a huge increase in holiday greens sales, selling over 100 more than the year before. Spruce tips were in short supply so we used multiple birch logs in assorted lengths to gain height for the focal point. Magnolia leaves, seeded eucalyptus, winterberry branches and juniper berries were used to highlight the containers, along with evergreen fillers. We added elegance with glittered and iced branches in natural, gold, white or red. We also created whimsical looks by adding snowman heads or larger millimeter balls with stars or hearts on sticks for splashes of color.
Tina Perkins, Manager, Winding Creek, Millbrook
We have recently seen a progression towards decorative ceramic pots for container planting. Customers use them for fairy gardens or succulents, which seem to be trending. Depending on the size of the pot, customers may use a mix of small indoor plants and succulents. Usually indoor plants can take lower light conditions or a porch location. Succulents have become more popular to use in containers as they generally require higher light conditions. Both types of plants like a lighter soil.
Can you tell me if the African daisy Osteospermum ‘Springstar Aurora’ can be winterized here? It is a healthy plant?
Those South African daisies could never endure a frigid winter here and should be considered annuals. Their daisy-like flowers with blue centers open only in sunlight and bloom best in early summer or later when summer days cool down. They can be seed-grown under lights.
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.
“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.
What trends do you see in container plantings, such as type of pot, materials, sun or shade, foliage or flowers.
Where can I send a letter to the editor?
My lilac had a grayish blight on the leaves this summer. What caused this and how can I prevent it?