Compiled by Stan Barrett and Connie Rayor, Colorado Master GardenersSM, Colorado State University Cooperative Extension, Denver County.
They may be getting insufficient sun or too much nitrogen. Daylilies need at least six hours of sunshine a day. Also, high-nitrogen fertilizer causes them to produce lots of leaves at the expense of flowers. Apply a balanced (10-10-10) fertilizer in the early summer for best blooming.
I planted some peonies two or three years ago. They look very healthy, but have never flowered. What causes this?
Peonies planted too deeply may never bloom; make sure the buds at the top of the roots are covered by no more than 1 inch of soil. Plant where they will get full sun--at least 6 hours per day.
My flower beds seem to be infested with earwigs this summer. Are they harmful to the flowers? If so, how can I get rid of them?
The European earwig is a very common inhabitant of flower beds. They tend to hide during the day in small dark spaces. They often feed on harmful insects and mites, but will also eat flower petals. Their population can increase rapidly as the growing season progresses, causing considerable damage to the ornamental garden.
They can be trapped by placing rolled up dampened newspapers in the flower beds in the morning, then collecting them in the evening. Heavy mulch in frequently irrigated areas provides ideal breeding conditions for earwigs. By reducing mulch thickness and allowing periodic drying of the flower beds, their population can be reduced; this solution is often adequate. In severe cases, insecticide baits containing carbaryl (Sevin) can be applied to the hiding places used by the earwigs during the day.
The leaves on my cherry tree are curled and twisted and are spotted with clear, sticky specks and sooty black patches. What is attacking them?
Black cherry aphids. These 1/8-inch long pear shaped insects range in color from pale tan to very dark brown. In the fall the adult female lays eggs on buds or small branches. The eggs hatch in the spring when the buds open. The aphids suck the juices from the plant and excrete "honeydew" which covers the leaves and fruit, creating ideal conditions for the growth of sooty mold (the black patches you saw).
To discourage the aphids, the following steps can be taken:
On my grape vine, the new buds have holes chewed in them; the new leaves are almost destroyed and I am getting very few grapes.
The culprit is probably the grape flea beetle. These are dark shiny insects, about 3/16-inch long. The adults emerge in spring and lay their eggs in cracks in the bark of grapevines. Emerging larvae are brown with black spots. The larvae feed for a month then pupate in the soil for several weeks before reappearing as adults.
What to do:
Our crabapple tree looks like it's been in a fire. The twigs look scorched and bent over at the tips. The leaves are still on the tree, but a lot of them are shriveled and crispy brown. What happened?
My maple tree is already losing a lot of leaves and it's only July! The bottom branches are almost bare, and the few leaves still on those branches are starting to change color. What's going on?
It sounds as though your tree is suffering from over-watering that may have occurred
earlier this year. Too much water in the soil keeps roots from getting the oxygen they
need. Maples, ash, aspen, honeylocust, and birch are among the most susceptible to this
drowning condition. The symptoms usually show up first at the bottom and the inside of the
tree close to the trunk.
The edges of the leaves on my shade tree are turning brown. Is this some sort of disease? What can I do?
If the leaves on the top of the tree and on the outer parts of the branches, were the
affected first, it's likely that the problem is drought injury caused our hot, dry summer
and dry winter. This environmental disorder occurs on evergreens, as well as on deciduous
trees. The damage you see cannot be reversed.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010