Monthly Q&A – September 2022

Our expert gardeners, Emma Crawforth and David Hurrion, are here to answer your gardening questions every month. Watch their answers below, and don’t forget to submit your questions for next month’s Q&A.

How to Reuse Old Compost

Compost is a valuable resource for gardeners, but what do you do with old compost? Here are a few ideas:

• Add it to your garden beds. Old compost can be mixed into your garden soil to improve its structure and fertility.
• Use it as a mulch. Spread old compost around your plants to help retain moisture and suppress weeds.
• Make compost tea. Steep old compost in water to create a nutrient-rich liquid that can be used to water your plants.

Should You Use Pot Feet or Saucers Under Your Containers?

Pot feet and saucers can be used to elevate containers off the ground, which has several benefits:

• Improves drainage. Elevating containers allows excess water to drain away, preventing root rot.
• Reduces heat stress. The air circulation under elevated containers helps to keep the soil cooler, reducing heat stress on plants.
• Prevents pests. Keeping containers off the ground helps to deter pests that may crawl from the soil into your plants.

My Lawn Looks Terrible After Summer, and Crows Are Pecking It. What Can I Do?

A combination of summer heat and drought can take a toll on your lawn, making it look brown and patchy. Crows may also be pecking at your lawn, searching for grubs or other insects. Here are a few tips to revive your lawn:

• Water deeply and regularly. Water your lawn deeply and infrequently, rather than shallowly and often. This encourages deep root growth and helps the lawn to withstand drought.
• Aerate your lawn. Aeration helps to break up compacted soil and allow water and nutrients to reach the roots.
• Fertilize your lawn. Fertilizing your lawn in the fall helps to strengthen the grass and prepare it for winter.
• Control crows. Crows can be deterred by using scarecrows, reflective tape, or other deterrents.

My Wisteria Has Died, but Is Shooting From the Base. Will Those New Shoots Flower?

Wisteria plants can sometimes die back to the ground, but they often send up new shoots from the base. These new shoots will eventually flower, but it may take several years. To encourage flowering, make sure to give your wisteria plenty of sunlight and water, and fertilize it regularly.

My Plum Tree Has Brown Rot. What Should I Do?

Brown rot is a fungal disease that can affect plum trees. It causes the fruit to rot and can also damage the leaves and branches. To control brown rot, remove any infected fruit and leaves from the tree. You can also spray the tree with a fungicide.

Additional Expert Answers

• What is the best way to revive badly dehydrated potted hydrangeas?
  • Water the hydrangeas deeply and regularly.
  • Place the hydrangeas in a shady spot.
  • Prune off any dead or damaged leaves.
• I often read about adding ‘loam’ to compost, but what is ‘loam’?
  • Loam is a type of soil that is composed of a mixture of sand, silt, and clay. It is a good all-purpose soil for gardening.
• My roses are covered in black spot. I don’t want to spray them. Are there any other methods to control it?
  • Remove any infected leaves from the roses.
  • Water the roses at the base of the plant, avoiding getting the leaves wet.
  • Apply a layer of mulch around the roses to help suppress the fungus.
• Why have my runner beans failed?
  • Runner beans need plenty of sunlight and support to grow well.
  • Make sure your runner beans are getting at least 6 hours of sunlight per day.
  • Provide a trellis or other support for the beans to climb on.
• Lots of my brassicas have grown with no center – cauliflowers with no curds, cabbages with no heart, calabrese with no heads. What is the cause?
  • This is likely due to a lack of boron in the soil.
  • Apply a boron fertilizer to your soil to help prevent this problem.

Submit Your Questions for Next Month’s Q&A

To submit your gardening questions for next month’s Q&A, please send an email to [email protected]

Our experts will answer a selection of the questions they receive, and share the advice at the end of the month.

Get Expert Gardening Advice

Every month, our gardening experts answer your questions. Watch their answers below and come back next month to submit your own question.

Questions Answered This Month

• How can I protect my greenhouse plants over the winter?
• How do I winter mulch perennials without burying their crowns?
• Can I improve the flowering of an old climbing rose?
• Should I remove a variegated alder tree with coral spots on its bark?
• How do I get rid of worm casts in my lawn?

Previous Q&A Sessions

• October:
  • How to retain water in peat-free compost
  • How to prune raspberries without knowing their type
  • What to do with unripe figs on a tree
  • How to get rid of fuchsia gall mite
  • Whether to pot or plant autumn sale perennials
• September:
  • How to reuse old compost
  • Whether to use pot feet or saucers for containers
  • How to fix a lawn damaged by summer and crows
  • Whether new shoots on a dead wisteria will flower
  • What to do with a plum tree with brown rot
• August:
  • How to revive dehydrated potted hydrangeas
  • What is “loam” in compost
  • How to control black spot on roses without spraying
  • Why runner beans have failed
  • Why brassicas have grown without a center
• July:
  • How often to water dahlias and sweet peas
  • How to treat powdery mildew on plants
  • When to take cuttings of leggy pinks
  • Why vegetable plants are all leaves and no fruit
  • Whether to cut back non-fruiting stems on summer-fruiting raspberries

Submit Your Question

As a Premium member, you can submit your gardening questions to our experts each month. They will choose a selection of questions to answer and share their advice at the end of the month.

Please note that you will not receive an individual response. Come back later in the month to see if your question has been answered.

Introduction

Plum armillaria root rot, also known as mushroom root rot or oak root rot, is a serious fungal disease that can affect a wide range of trees, including plum trees. This disease is caused by a fungus that attacks the roots of trees, causing them to rot and eventually leading to the death of the tree.

Symptoms of Plum Armillaria Root Rot

The symptoms of plum armillaria root rot can vary depending on the stage of the disease. In the early stages, trees may show signs of yellowing leaves, stunted growth, and wilting. As the disease progresses, trees may develop rotted stems and roots, with black, stringy strands growing on the larger roots. A creamy white or yellowish, felt-like fungal growth may also be visible under the bark. In the final stages of the disease, trees may die rapidly or decline slowly over time.

Spread of Plum Armillaria Root Rot

Plum armillaria root rot spreads primarily through contact between diseased and healthy roots. The fungus can also spread through the air via spores, which can infect unhealthy or damaged wood.

Preventing Plum Armillaria Root Rot

There is no cure for plum armillaria root rot, but there are steps you can take to prevent the disease from infecting your trees:

• Avoid planting plum trees in soil that has been affected by armillaria root rot. The fungus can survive in the soil for decades, so it is important to choose a planting site that has not been previously infected.
• Plant trees in well-drained soil. Trees that are planted in consistently soggy soil are more likely to develop armillaria root rot.
• Water trees well, but avoid overwatering. Trees that are stressed by drought are more likely to develop the fungus. However, overwatering can also create conditions that are favorable for the fungus to grow.
• Fertilize plum trees in late winter or early spring. Fertilizing trees can help them to stay healthy and resist disease.
• Replace diseased trees with resistant varieties. If a tree becomes infected with armillaria root rot, it is important to remove it and replace it with a variety that is resistant to the disease. Some resistant varieties include:
  • Tulip tree
  • White fir
  • Holly
  • Cherry
  • Bald cypress
  • Ginkgo
  • Hackberry
  • Sweetgum
  • Eucalyptus

Conclusion

Plum armillaria root rot is a serious disease that can cause significant damage to trees. By understanding the symptoms of the disease and taking steps to prevent it, you can help to protect your trees from this devastating fungus.

Additional Tips for Preventing Plum Armillaria Root Rot

• Mulch around trees to help retain moisture and suppress weeds.
• Avoid wounding trees, as wounds can provide an entry point for the fungus.
• Keep trees healthy by providing them with adequate water, fertilizer, and sunlight.
• Inspect trees regularly for signs of disease. If you suspect that a tree may be infected with armillaria root rot, contact a certified arborist for diagnosis and treatment recommendations.

By following these tips, you can help to keep your plum trees healthy and free from armillaria root rot.