This is the Q&A for the Yard and Garden show for May 7, 2021. 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 30, 2021. 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
- The first caller of the day has boxwoods that have turned brown. What is causing this and how can the look be improved?
A. These broadleaf evergreens are suffering from winter injury. It is due to the extreme cold we had in February. If twigs are not dry and brittle then leave them until late May to determine how much new growth will develop then prune out the brown areas. Avoid pruning into bare stems to allow for regrowth.
2. This caller has a linden tree that is growing well, but occasionally branches die back and the bark around the dieback is peeling. What is causing this?
A. This could be from squirrel damage. They chew on the branches causing the end to die off and then the bark will peel back from there. You can go in and cut out the ends of the branches that are dead from this damage.
3. A caller has knockout roses. The tops of the roses are not greening up still. What is wrong?
A. This is due to winter injury from the harsh winter. Now that the rest of the plants have greened up you can begin to see where the dead ends and living tissue begins. You can prune out the dead areas and the roses will be just fine.
4. This caller has rhubarb that was planted last year. It bloomed, but she cut the stalks off when that happened. Last year, the growth was a lot better than it is so far this year. Can she use water from the chickens that has manure in it to water the plants to help fertilize it?
A. Yes, you can use chicken manure as a fertilizer for rhubarb plants and the manure water would help to ensure that you don’t put too much on the plants and burn them because chicken manure is quite high in Nitrogen content. However, it is advised to only use manure on edible plants in the fall to ensure that all the bacteria can sufficiently break down prior to consumption. Also, when applying, it would be best to only use the water around the plants and not directly on the leaves.
5. How do you plant poppy’s from the seed that was already collected?
A. Wait a little longer this spring to ensure that the ground temperature has risen to a more suitable temperature for poppy germination and growth. Sow the seed across an area fairly shallow, only 1/4 inch deep, then water it in and maintain even moisture. You can sow the seed in pots or other containers to get them started then transplant the plants later in the year if desired.
6. A caller has some cedar trees that are 30 years old and have been healthy and looking great. Recently, they are turning a faint brown color, especially toward the exposed side of the trees. Is this just winter injury?
A. Yes, this could be, especially since it is on the exposed side of the trees. They should grow out of it. It would help the overall health of the trees if they are watered some now since they are stressed.
7. This caller has 2 Rose of Sharon plants. Last year they had bagworms on them and she picked them all off. Now, they are not greening up. What is causing this?
A. This is due to the slow warm up this spring and extremely cold winter we just got through. Give them time, they should be fine in a couple of weeks. You can scratch at the smaller branches with your fingernail. If the cambium layer is green under the bark the plant is still alive, if it is brown, it is dead.
8. This caller has rhubarb plants that are older and have been in place for a while. She said her plants are not growing very large yet this spring. What is causing that?
A. They could be slow growing this spring due to the colder temperatures, give them time to get through that. The soil temperatures have been quite cool which would cause a slow down in growth. Also, after discussing her plants she said they have never been fertilized. The plants would benefit from a fertilizer application. She can use a general fertilizer now, granular form applied around the plants or in the fall she can incorporate some manure around the plants.
9. A caller has some blue spruce trees trees that had brown needles last year. They sprayed the trees last year but they still look brown. What is wrong and how can it be corrected?
A. Blue spruces have been dealing with quiet a few different issues lately. One of the main problems that is causing the brown needles is a disease called needle cast. If they sprayed a little late last year, the sprays wouldn’t be as effective. It would be best to spray the trees now and again in a couple of weeks with copper fungicides or Daconil. This could also be from spidermites which can be controlled with a strong spray of water as they show up and begin damaging the plants.
10. If a garden gets hit with pesticide spray drift, can the produce still be consumed?
A. There is no way to know for sure if or when the produce will be safe to consume. If you don’t know what pesticide was applied, you can’t know how long it will be in the plant and in the produce.
11. This caller is having trouble growing different types of melons in his garden. He said that the plant will grow and set on melons then the vines seem to die out. He is fertilizing and watering the plants properly. What is causing this and how can he get his melons to grow better?
A. This could be from squash vine borer. Especially since the plants seem to die very quickly in the mid-summer. They can be managed by spraying sevin, eight, or bifenthrin. You will need to begin spraying in the beginning of June when the borers become active and spray every couple of weeks, in accordance with the label, through June and July. Concentrate the sprays to the base of the plants where the female borer is laying her eggs. You can also use row covers or wrap the base of the plant in aluminum foil to disrupt the egg laying.
12. What is the best time to transplant peonies?
A. Peonies are best transplanted in the fall when the plants begin to turn brown. If you are dividing while transplanting, make sure that there are at least 3-5 of the pink buds (eyes) per division. Also, make sure that the plants are re-planted at the same depth. If peonies are planted too deeply, they will not bloom. You can mark the depth by tying a twist tie or some other product tied onto the stem before digging up or mark it with a marker to ensure they are replanted to the correct depth.
13. Should Canna bulbs be planted in full sun or part shade?
A. They should be planted in full sun for best growth and flower production.
14. A caller is looking to add a privacy windbreak. Would the Giant Arborvitae be a good tree selection for this?
A. They would be ok, but you would be better off with something that is more winter hardy. In the past few years, arborvitae have seen a large amount of damage. They are better grown in more protected locations in the landscape rather than as a windbreak. Since you are looking for something smaller to plant under power lines, you could look at Yew bushes or privet, serviceberry, or viburnum. Also, there are some newer varieties of spruce and pine that would remain smaller for the location.
15. The final question of the day was about boxwoods turning brown. What is causing this?
A. They are suffering from winter injury. It is due to the extreme cold we had in February. If twigs are not dry and brittle then leave them until late May to determine how much new growth will develop then prune out the brown areas. Avoid pruning into bare stems to allow for regrowth.
*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.
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Plants and Pests with Nicole 