This is the Q&A for the Yard and Garden show for May 27, 2016. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 5, 2016. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.
Guest Host: Dick Campbell, Owner of Campbell’s Nursery in Lincoln
1. The first question of the day came via email. A listener wanted to know how to control clover in their lawn?
A. Clover is best managed in the fall months when it is pulling nutrients from the leaves into the roots, it will take the chemical into the roots as well. Products with triclopyr work best, but 2,4-D will work as well. Make 2-3 applications in September and October for best control.
2. A walk-in question was for identification of a weed.
A. This weed is mallow. It is a difficult weed that will move throughout our gardens. It can be controlled with a careful application of Glyphosate (Roundup). Be careful not to spray any other plants with the glyphosate product.
3. A caller wanted to know when she can transplant daylilies and Iris?
A. The daylily could be transplanted now. It would be best to move these in the spring or in the fall, but daylilies are a tough plant and would be fine if moved now as long as they are kept well watered when it is hot because the root system isn’t developed at the new location yet. Iris would be best if transplanted in the fall.
4. A caller has earthworms making his lawn uneven. What can be done to control those? This caller also wanted to know if he can water houseplants with water that goes through a water softener?
A. Earthworms are very beneficial to our soils as they reduce compaction and add organic matter back to our soils. The damage from them is only seen for a couple of weeks in the spring with rains. If you can deal with it for a short time, it is best to avoid treating for them. If you have to treat, Sevin insecticide does have some management capabilities for your lawn. As for watering the houseplants with water from a water softener, it is best to use water prior to the softener due to the increase of salts in the water.
5. This caller wants to know how far away from the house a shade plant should be planted? She also wants to know how she can manage grass in Iris’?
A. Spacing the tree from the house depends on the tree chosen and what the full size of that tree is. For many of the oak or maple shade trees, it is best to go 25-35 feet or farther from the house to ensure no problems develop as the tree grows. The grass in the Iris bed can be controlled with Grass-B-Gon.
6. A caller has a cherry tree that the top broke off but it is still attached to the main trunk. Can it be saved?
A. There is no way to re-attach a broken off branch. This branch will have to be removed. Because this is the only branch that is still producing leaves and cherries, the tree should be removed and replaced.
7. A caller has 2 rhubarb patches that were damaged badly by hail. The leaves look terrible. Should those leaves be removed or left on the plant?
A. If there are new leaves growing below the damaged leaves, the damaged leaves can be removed. However, if those damaged leaves are all that is alive on the plant right now, they should be left on the plant until new leaves begin to grow so that the plant can still grow and build nutrients for next spring.
8. A sample was brought in of a trumpet vine with many little insect all over the stem, leaves, and flowers. The plant has been sprayed with Sevin with no control. What can be done for this trumpet vine?
A. Sevin is not an effective method of control for aphids. In high populations you can use Eight or Malathion. Aphids are not very damaging to our plants and they are fairly short lived. Given time, predatory insects will move onto the aphids to control them without chemicals.
9. This caller was looking into planting apple trees and found there is a disease called cedar-apple rust. Is this a concerning disease here and what should be done to avoid problems with it?
A. Yes, cedar-apple rust is a damaging problem for apple trees. The spores can spread up to 2 miles, so it is best to plant a resistant apple tree cultivar. It is also good to look for cultivars that are resistant to apple scab. For choosing your cultivar, here is a publication from Purdue that lists common apple tree varieties and their disease susceptibility: Disease Susceptibility of Common Apple Cultivars
10. A sample was brought in of a tulip tree with leaves that are puckered and rolled downward. What would be the problem with this tree?
A. This tree has aphids on the underside of the leaves that are sucking the juices out of the leaves. Aphids are not terribly damaging to our plants and are fairly short lived. In high populations you can use Eight or Malathion.
11. Is there a dry granular weed killer for the lawn? When is the time to move gooseberries, iris, peonies, and rhubarb?
A. Fertilome is a good dry, granular weed killer. This is best applied early in the morning so it will stick to the leaf blades with the morning dew. Gooseberries should be moved after dormancy. Iris and peonies should be moved in the fall, typically in September when the tops begin to turn yellow. The rhubarb should be moved after they are dormant in the fall or early spring.
12. This caller has asparagus that has been planted in this location for many years and is now dying out. She fertilizes 2-3 times per year with a general fertilizer. What is causing this problem and can it be fixed? She also wants to know if she can use canning salt or Epsom salt in her garden? And, finally, she wants to know what to do for the aphids on her honeysuckle?
A. Asparagus will die out due to age. It would be beneficial to dig it up this fall after it goes dormant and divide the plants to replant as individual clumps. When replanting, sprinkle some bone meal in the hole to help with fertility. As for using epsom salt in the garden, this is not necessary. Epsom salt is magnesium sulfate which is in good supply in Nebraska soils. If nutrients are necessary in your garden, it is best to use a general purpose fertilizer. Canning salt can harm your plants and damage the soil. It is not a recommended practice to use any type of salt in your garden. As for the honeysuckle aphids, those should be controlled with Eight or Malathion. The aphids on honeysuckle can cause witches broom to the plant so they should be controlled.
13. Do raspberries and blackberries need to be grown on a trellis?
A. Yes, a trellis or an espalier would be a good way to grow them. Here is a good guide to growing raspberries and blackberries from Missouri Extension
14. Can red and black raspberries be planted together?
A. Don’t plant them within 20 feet of each other or they will cross pollinate and the fruits will not taste as good.
15. A caller has rhubarb that is shooting up stalks with seeds on them. What should be done with those?
A. Those seed stalks should be removed. Cut the stalk off at the ground. If left the plant will put energy into producing seed that should be stored for leaf and stalk production.
16. The last caller of the day has a mandevilla plant that is growing outdoors in a pot with a trellis. The leaves are now turning yellow and black. What is causing this and how can it be managed?
A. This is a moisture issue. The heavy rains this year are causing a leaf fungus to occur. A rose and flower systemic containing a fungicide can be applied to the plant to help reduce the disease.