This is the Q&A for the Yard and Garden show for May 29, 2015. 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 July 31, 2015. 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: John Fech, Extension Educator in Douglas & Sarpy Counties
1. A caller had fine webbing on her tomatoes, what is it and how can it be controlled? She also wondered about using blossom set on her tomatoes?
A: The fine webbing on the tomatoes would be spidermites. These can be controlled with a strong spray of water on the plants to knock the mites off and kill them. As for the blossom set, is not recommended as it does not have strong research to back the effectiveness of it.
2. A lady had a river birch and a dogwood shrub that are not leafing out at the top. Why is this?
A: The plants are going through environmental stress. This spring has been warm followed by very cold to warmer again and now just cool, cloudy, rainy weather. That follows 3 years of stressful environmental conditions starting with the drought in 2015. Many of our plants are experiencing a degree of winterkill due to these events, where the top of the plant is not leafing out but the bottom of the plant is. Many of our plants will eventually fully leaf out or just have some dead branches through them. With the dogwood, those dead branches can be pruned back, but wait 2 more weeks to see if any more of the plant comes back. With the river birch, it is not advised to top a tree, so the pruning practices will be more difficult and it would be best to consult an arborist for that.
3. A caller has an Austrian Pine where the new growth is browning and lighter green, whereas the rest of the tree is dark colored. What is wrong with it?
A: The needles at this point are not fully elongated due to the late spring events. Give the tree time to fully come out of the winter dormancy period to determine the color differences. If at that point there is still a problem, email me or your local extension office for more information.
4. This caller has a Japanese Lilac tree that has brown branches with no leaves on them. What should be done with those branches?
A: Scrape the branches with a fingernail or pocket knife to see if there is any green tissue under the bark in the cambium layer. If underneath is brown it is a dead branch. Either way, wait until around June 15 to see if the branches will come back from winter dormancy. If not, then the dead branches can be removed at that point. Don’t remove any live tissue from the tree at that time of the year.
5. A caller wanted to know if you can get multiple cuttings from a broccoli plant?
A: Broccoli is a tough plant to grow in Nebraska because in typical years it gets too hot too soon in the summer to provide an efficient harvest. It is suggested to grow broccoli as a fall crop. This year, however, is a good year for broccoli in the spring due to the slow warm up we have seen. As long as you only cut out the broccoli florets, you can leave the leaves and provide additional side buds that can be harvested for broccoli meals.
6. This caller has a large silver maple in their yard and now they are finding multiple small seedlings of maples all around their landscape. How can those seedlings be controlled?
A: Mowing them off is the best practice or pruning them out while they are small and easier to control. Do not spray them with any chemicals for control because they could be suckers coming up off of the roots of the main plant and any chemical applied to root suckers can kill the entire tree. These seedlings could also be from the seeds that fall from the trees in samaras that resemble helicopters, but determining the difference is very difficult and it is just easier to only cut the seedlings rather than treat them with a chemical and risk harming the main tree that is enjoyed in your yard.
7. This caller has cherry trees that have suckers coming out from the base of the plant. What can be done to control those?
A: These suckers will have to pruned off repeatedly with pruners not the lawnmower. They are attached to the main plant and any chemical attempts would harm and possibly kill the main cherry tree. Typically, trees will begin to sucker when they are stressed. Ensure that the tree is well taken care of and healthy by providing it with a mulch ring 2-3 inches deep and as wide as they can make it. Water the tree at a slow trickle for 30-60 minutes one time a week during the hot part of the summer and only once every two weeks during the spring and fall.
8. This woman was wondering if now was the time to prune her snowball bush that is just finishing up the blooming period? She also wanted to know if this was the time to apply weed and feed to her lawn?
A: Now would be a great time to prune that spring blooming shrub. The rule of thumb is to prune spring blooming shrubs after they finish blooming for the year and prune summer blooming shrubs late in the winter before growth begins for the year. Now is the time to fertilize your lawn, but avoid using weed and feed products. The problem with a weed and feed product is that the weed control part of that needs to stay on the leaves and the feed portion needs to stay off of the leaves. It is a better practice to fertilize the entire lawn with only a fertilizer and spot spray with 2,4-D products only on the weeds in the lawn.
9. This caller’s daughter lives in Lincoln where flooding was a problem and she has a drainage ditch that has caused water to sit and is now concerned with mosquitoes. What can be done?
A: If the water is stagnant and there is no way to remove the water, it is best to use larvicides that are found in mosquito dunks that can be purchased at many box stores and garden centers. These mosquito dunks are not harmful to other wildlife or people.
10. This lady has a tree that has deer rubs on it. She placed a tree wrap tube on the tree and was curious about removal of the tree wrap.
A: The tree wraps and tubes are a great way to keep deer from damaging young, thin barked trees. They should only be left on for the winter months and then removed during the spring and summer. If left on they can girdle the tree if it gets too tight on the trunk and it can be a location for insects and diseases to get into the tree.
11. This caller has Ponderosa Pines that have brown needles that cover 80-90% of the tree. It is only a problem on 2 of the many Ponderosa Pines that are all planted together. They have been planted for about 5 years and have shown this browning over the entire tree for 2-3 years. What can be done for this problem?
A: This could be a root issue dealing with stem girdling roots or a watering issue. It is hard to determine, but might possibly be due to low watering. Water the plants slowly for 30-60 minutes weekly in the summer and once every two weeks during the spring and fall. These trees may not make it through, if it is a root issue digging them up after they have completely died would help solve the problem.
12. The final caller this week wanted to know how late in the season they should harvest their asparagus plants?
A: They do need a period through the summer to rest from being harvested so they can build sugars to help them get growing next spring. It is best to quit harvesting when the stalks develop ferns, when they get small and spindly, and/or when they get woody. This will give the plant plenty of time to recover from this years harvest and prepare for next years harvest.