Yard and Garden: July 6, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for July 6, 2018. 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 3, 2018. 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: Dennis Ferraro, Wildlife Specialist from UNL

1. The first caller of the day wants to know if borers from ash trees can get into his walnut trees?

A. Some native borers can be a problem in both ash and walnut trees, such as the redheaded ash borer which is a common borer in many of our trees in Nebraska. When the Emerald Ash Borer gets to southeast Nebraska, it will not be able to. EAB is a pest in Ash trees only.

He also wanted to know how to move woodchucks and not kill them?

A. Live trapping will work for woodchucks. Use cucumbers or corn to bait them and wire the trap open for a few days before actually activating the trap because woodchucks are very cautious and will not be trapped the first time or 2 into the trap. The woodchuck can then be relocated to within 100 yards of the trapped location. State regulations prohibit relocation farther than 100 yards. It would also work to change their nesting location. This woodchuck is found under a building, so if you can chase it out during the day then pack the hole tightly with road gravel will prevent them from coming back. For more information, visit the UNL Wildlife website on Woodchucks.

2. A caller has heard that bull snakes will keep rattle snakes away. Is this true?

A. These 2 types of snakes do get along but bull snakes are more aggressive hunters and can out-compete rattle snakes. Because of this, rattle snakes usually relocate to find food.

3. This caller has tomatoes with bumps along the stem of the plant. What is wrong with the plant?

A. There is nothing wrong with tomatoes that develop bumps along the stem. These are aerial roots which are common.

4. A caller has a white powdery substance on her peony plants. What causes this and how can it be controlled?

A. This is most likely powdery mildew on the peony plants. It is a common disease we see this time of the year. There is no need to treat the plants for it right now. The best control for powdery mildew is to cut off the plant in the fall when it dies back and destroy the infested plant material so the disease cannot overwinter. It will not kill the plants.

5. This caller has tomato plants with leaves that are turning yellow and the plant is not producing tomatoes, any flowers produced fall off. What is wrong with his tomato plant?

A. This is likely due to environmental stress or possibly Septoria leaf spot. Make sure that the plants are watered 1 inch of water per week, they have mulch, and they are being watered from below. If desired, a fungicide can be applied. For more information view this NebGuide on Leaf and Fruit Diseases of Tomatoes. The poor pollination is common this year due to the heat. Give the plants some time and they should start to produce.

6. A caller has a sycamore tree that is shedding bark. What is wrong with the tree?

A. It is normal for sycamore trees to lose some bark. It is a tree that has a camouflage bark appearance due to the fact that it sheds some bark. Nothing to worry about or to do to fix it.

7. This caller is growing petunias in a hanging basket and the leaves are turning yellow. What is wrong with them?

A. This could be due to environmental stress. Make sure they are kept watered and placed in a location where they get full sun. It might also be from spidermites, look closely at the plant to see if there is any very fine webbing. If so, use a strong spray of water to knock the spidermites off and kill them.

8. A caller has bindweed in his garden and in his lawn. What can be done to control it?

A. In the garden, use the “glove of death” which is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the stem and leaves of the bindweed to kill it. Basically, the idea is to keep it from flowering and producing more seed, hand pulling will help keep new seed from being deposited into the garden which can be viable for up to 60 years. In the fall, you can spray the lawn with a 2,4-D product.

9. How do you control purslane in the garden?

A. Purslane easily reproduces from cuttings so avoid hoeing or weed trimming through it while leaving pieces of the plant laying around on the ground throughout the garden. Purslane doesn’t like to be smothered, so a heavy mulch layer on the weed will help.

Gorgone Checkerspot Caterpillar
Gorgone Checkerspot Caterpillar

10. This caller has tiny, dark colored worms on her black-eyed Susan plant. She has used some Eight but she still has some. The leaves are also turning gray, how can she control the caterpillar?

A. This could be a checkerspot caterpillar. It is commonly found on sunflower, which is a closely related species of plant to this black-eyed Susan. This becomes a good pollinator butterfly. If she can relocate the caterpillars it would be best, or the Eight will just take some time to fully work on the caterpillars. The gray on the leaves is likely due to downy mildew or powdery mildew, not the caterpillars. Caterpillars will only chew holes out of the leaves, not leave any gray coloration to the leaves. Downy or powdery mildew are not very harmful to the plant and don’t need to be sprayed. In the fall, cut down the plant and discard the infected plant material so the disease is minimized for next year.

11. A caller has an ash tree that is about 15 years old and the outside leaves are now turning brown. What is wrong with it?

A. This could be due to leaf scorch due to the hot, dry conditions we have been facing lately. The tree should be fine, it will likely look rough the rest of the year. Make sure the tree has a mulch ring and that it is being watered for about an hour weekly with a sprinkler or slow trickle from the hose.

This caller also wondered about cougars in the area. He said he has seen a cougar with 4 cubs in the area. Will the cubs all stay here or will they move through to somewhere else?

A. Males can travel many miles and across the country. Females will stay around if there is food available and if a male doesn’t chase the female cubs away. The male cubs will likely move on when they get old enough to travel alone.

12. A caller has a tree that is pushing its roots up to be exposed out of the soil. What can be done about this?

A. Mulch will be the best option for these roots. The mulch will keep you from mowing over the roots which can damage the roots. Do NOT add soil on top of these exposed roots as that can limit oxygen for those roots and eventually kill the tree. You can make the area into a perennial garden under the tree, but do not raise the soil grade to do so and do not damage the roots to do so.

13. The final caller of the day wants to know why black crappie would be larger than white crappie?

A. This could be due to genes. The color gene may be linked to the size genes. So as the color is changed genetically, so is the size. It could also be that the predators in the area this caller was fishing in preferred eating the white crappie rather than the black crappie, causing only the smaller white crappie to be left with the larger black crappie. There are many factors that could lead to this difference in size between the 2 different colored crappie.

Hot Weather and Plants

Drought in a lawn
Drought lawn photo from John Fech, Nebraska Extension Educator in Douglas/Sarpy Counties.

It’s hard to say what normal Nebraska weather is. However, this year has been particularly difficult for our plants. The quick change from cool to hot has caused some lasting effects on our plants. Some of the common problems we have been seeing this year include: leaf scorch, drought problems, and poor pollination.

Leaf Scorch

Leaf scorch can happen on the leaves of our trees, vegetable plants, and other garden plants. Leaf scorch causes the tips of leaves of many plants to turn brown and crispy. The abrupt change in our environment from cold to hot and humid left even the most well-adapted plants struggling to stay green. Even plants that are not in full sun will be affected from the high temperatures, such as hostas that are planted in shade.

When the plant is unable to take up enough water, the leaf tissue that is farthest from the major veins will dehydrate first causing leaf margins to scorch first. Leaf scorch is not necessarily caused from lack of water, it is because the plants cannot take in enough water to compensate for what is being lost through transpiration. The moisture may be present around the roots, it just is not entering the plant as fast as it is leaving it.

Do not automatically go out an water the plants that are showing scorch. Watering may be necessary, but don’t overwater. Ensure that the plants have mulch around them and check the soil moisture before watering.

Dry Conditions

In these dry conditions we have faced through most of the growing season, it is important to remember to water your plants. But, it is always a good idea to check soil moisture before watering to help reduce the problems with overwatering. Most of our plants need about 1 inch of water per week, if they don’t receive that from precipitation, they need it from irrigation. If a screwdriver or dowel pushes into the ground easily moisture is sufficient around the plant. For trees the screwdriver should go down 12-18 inches, for perennials it should go down 6-8 inches and for turf and vegetables it should go down 4-6 inches.

Poor Pollination

The heat we are facing is also causing some slight problems with poor pollination and there are problems we could face later as our fruits begin to develop, abnormally. In this heat there is a condition called blossom drop that can occur. It is when the flowers abort and fall from the plant rather than developing into a fruit. This can also be due to drought conditions, which we are also facing. When temperatures reach 93 degrees F, pollen becomes sterilized, so even if they get pollinated, they are not fertilized and fruits will not develop.

The heat and drought we have been dealing with can also cause small fruit development and sunscald. Sunscald happens in high temperatures when our fruits develop without leaf cover. Don’t prune tomatoes too heavily or it can leave your fruits open to damage from sunscald.

We could also have problems with bitter tasting cucumbers this year. Cucumbers produce a chemical called cucurbitacin, which is bitter in flavor. Most cucumbers that we eat now have low amounts of this chemical, but they can produce more due to environmental stress. Uneven watering, drought issues, and high temperatures can all lead to the build-up of cucurbitacin. It is likely this year we may have a problem with that, and there is no way to fix it. Just be sure to try out your cucumbers while you are cutting them up for your recipes.

The leaf scorch information for this article came from Kathleen Cue, Dodge County Extension Educator.