Master Gardener – Search

Searching: Disease
If you don't see the answer you're looking for, try submitting your question.
Declining Rose Bushes
-
Date Posted: Wed, Aug 20 - 12:18 am
- We have a row of drift roses out from for the last 8 years, last year once bush died totally after pruning and was replaced but two others appear to have dying branches in places but are blooming in others. Do you have any recommendations? They previously were huge and bloomed all summer.
- Thank you for reaching out about your drift roses. After 8 years, it’s not uncommon to see some decline in vigor, and the symptoms you’re describing (a bush dying after pruning, and others showing partial dieback while still blooming) may have several contributing factors. Possible Causes Age & Natural Decline: Drift roses, while hardy, often start to lose vigor after 7–10 years. Decline in individual plants can be expected over time. Pruning Stress: If roses are pruned too severely or at the wrong time (late fall/early winter), it can stress the plant and increase vulnerability to dieback. Canker or Dieback Disease: Fungal cankers can cause branches to brown and die back while other parts of the shrub continue to bloom. Look for discolored, sunken, or shriveled stems. Root Stress: After many years in the same spot, soil compaction, poor drainage, or root competition from nearby shrubs can weaken roses. Environmental Stress: Last winter’s cold snaps, summer drought, or inconsistent watering can also contribute. Recommendations Inspect the Canes: Cut into affected stems. If the wood inside is brown rather than green/white, prune those branches back to healthy tissue. Sterilize pruners between cuts (70% alcohol or 10% bleach solution). Monitor for Pests/Disease: Check for signs of fungal cankers, crown gall, or borers. Mulch & Soil Health: Refresh mulch to 2–3 inches (but keep away from the crown). Consider lightly amending with compost to improve soil structure and nutrients. Watering Practices: Provide consistent deep watering during dry spells, especially since stressed plants are more susceptible to disease. Rejuvenation Option: If more bushes continue declining, you may want to replace them gradually. Consider rotating in disease-resistant shrub roses or other flowering shrubs to diversify and reduce the chance of future loss. Since one plant has already died and others are showing decline, you may be at the natural replacement stage for part of the row. Healthy roses can last many years, but staggered replacement every few years can keep the planting full and vibrant.
Question
Answer
Transplanting a peach tree
-
Date Posted: Thu, Aug 14 - 5:34 pm
- I need to transplant this peach tree but know next to nothing about when/how/where. Would love advice!
- Thank you for reaching out! Peach trees can grow successfully in the Richmond area when given the right conditions and care. Since your tree is currently in a pot, here are some steps and tips to guide you through transplanting it into the ground: Best Time to Transplant Late fall to early spring (after leaf drop but before buds swell) is ideal. In Richmond, that’s typically November through March when the tree is dormant. This reduces stress and gives roots time to establish before summer heat. Choosing a Planting Site: Sunlight: Choose a location with full sun — at least 6–8 hours daily. Soil: Well-drained, loamy soil with a pH of 6.0–6.5 is best. Avoid low areas where water collects. Soil test kits can be found at local Richmond Public Libraries Air Circulation: Good airflow helps reduce fungal diseases. How to Transplant: Dig a hole twice as wide as the root ball and just as deep. Loosen the surrounding soil to encourage root spread. Gently slide the tree out of the pot, loosening any tightly wound roots. Trim circling roots to prevent girdling. Place the tree so the root flare (where roots meet trunk) is level with or slightly above ground level. Fill with native soil (you can mix in some compost if soil quality is poor). Water deeply to remove air pockets. Apply 2–4 inches of mulch around the base, keeping it a few inches away from the trunk. This helps conserve moisture and regulate temperature. After planting: Water deeply once a week during the first growing season, more often in hot/dry spells. Lightly prune in late winter to shape and remove damaged branches. Young peach trees can be susceptible to deer, rabbits, and voles, so consider fencing or trunk guards. Good luck with your peach tree!! We wish you lots of success! Thanks again for reaching out.
Question
Answer
Serviceberry TLC
-
Date Posted: Thu, Jul 31 - 10:56 pm
- My service berry tree has split bark in several places and there may be insects in the bark. There are many yellow leaves. The tree doesn’t look healthy. I planted it in the fall. Is there anything I can do to save it?
- Thank you for reaching out! It sounds like your serviceberry tree is experiencing some stress, but we’ll do our best to help you support its recovery. Yellowing leaves can indicate a few things: transplant shock, water stress, or even nutrient deficiency. This is common in newly planted trees as they adjust to their environment. Split bark can also be a sign of environmental stress like rapid temperature changes in winter (known as frost cracks or sunscald), mechanical injury (e.g., weed trimmers or animals), and overwatering or underwatering. Unfortunately, splits in the bark can make the tree more susceptible to insect or disease invasion. If you see insects, they may be opportunists rather than the primary cause. What You Can Do: Inspect the trunk: Look closely at any insects you find. If you can, take a clear photo to try to ID. Mulch properly: Place a 2–3 inch layer of mulch around the base of the tree (keeping it a few inches away from the trunk) to regulate soil temperature and moisture. Water consistently: Deeply water once a week during dry periods. Avoid overwatering—serviceberries prefer moist but well-drained soil. Prune carefully: Remove any obviously dead or damaged branches, but avoid heavy pruning during stress periods. Avoid fertilizer for now: Wait until the tree is more stable before fertilizing. It may take some time for your serviceberry to bounce back, but with proper care and monitoring, it could still recover. We wish you the best! For more information, check out: https://piedmontmastergardeners.org/article/serviceberry/
Question
Answer
Hydrangea Pruning
-
Date Posted: Wed, Jun 04 - 1:52 am
- Hello! My hydrangeas need some help. I inherited them with my new to me house in late fall, so this spring was my first opportunity to prune. They were already overgrown from the past owners. For the big leaf hydrangeas: I missed the fall pruning, so these haven't had a haircut since who knows when. The branches are getting weighed down from the weight of the flower and leaves, and the plant is very leggy. Should I try and start selectively and slowly clipping them back now or wait until they're done blooming and do it one big chop? If now, do I cut the old leggy wood back, or just the new green branches that are stemming from the old leggy wood (the two blooms on the top of the left bush are an example)? For the panicle hydrangea in the middle: I cut what I thought was way back this spring, but clearly not enough! Should I be trying to selectively trim some of this back now or bite the bullet and wait until spring and do a big chop? It's so tall and it's only May! Thank you!
- Thanks for reaching out—and congratulations on your new home and garden! It sounds like you’re giving your hydrangeas some thoughtful attention, which they’ll definitely appreciate. The blooms are beautiful! Here’s a breakdown of how to approach pruning both your bigleaf hydrangeas (Hydrangea macrophylla) and your panicle hydrangea (Hydrangea paniculata): Bigleaf Hydrangeas : These bloom on old wood, meaning the flower buds for this summer formed last year. That’s why heavy spring pruning can often result in fewer blooms. Since yours are blooming now, I'd recommend that you hold off on major pruning until after they finish flowering—typically by mid to late summer. Then you can: Remove about 1/3 of the oldest, leggiest stems at the base to encourage new growth from the bottom and lightly shape the plant by shortening stems that look untidy or weighed down. Avoid pruning after August, however, as that risks cutting off next year’s flower buds. In the meantime, if any branches are flopping badly or blocking paths, you can do a light, selective trim now—just avoid heavy cuts that remove flower buds. Panicle Hydrangeas: These bloom on new wood, so you have more flexibility with timing. You’re absolutely right that they can grow quickly in spring! For now, you can lightly thin or shorten a few of the tallest stems to maintain a more manageable shape but avoid cutting more than 1/3 of the plant this time of year. If it’s still too tall for your space, plan for a more significant structural pruning next late winter/early spring, before new growth starts. General Tips: Always cut just above a pair of healthy buds or a leaf node. Use clean, sharp pruners to avoid disease. Consider adding mulch and checking soil drainage if plants look stressed or leggy—bigleaf hydrangeas especially like evenly moist (but not soggy) soil.
Question
Answer
Rhododendron Questions
-
Date Posted: Thu, May 08 - 11:14 pm
- I have an established rhododendron and a couple of questions 1. Some leaves tern yellow and die and fall off 2. Others show yellowing but remain 3. New shoots form at the base but die never to mature 4 is there any way to encourage new growth on the old branches
- Thanks for reaching out with your rhododendron questions! You’ve made some great observations, and your plant is definitely trying to tell you something. Here are a few possible explanations and tips based on what you described: Yellowing and Leaf Drop: Some yellowing and leaf drop is normal, especially for older inner leaves. However, widespread or early-season yellowing in Richmond can also point to stress from heat or underlying root issues, particularly since rhododendrons are naturally cool-climate, understory plants. Our warm springs and hot summers can make them more susceptible to systemic diseases or environmental stress. Persistent Yellow Leaves: This could be a sign of sun stress—rhododendrons prefer morning sun with dappled afternoon shade. Too much direct, hot afternoon sun can cause the kind of yellowing you're seeing. Poor drainage or soil that’s too alkaline can also cause nutrient uptake issues, leading to chlorosis (leaf yellowing). New Shoots Dying Back: When new shoots at the base fail to mature, it often points to root zone stress, such as poor drainage, fungal root diseases, or heat stress. Check that mulch isn't piled too high against the base and that the soil is staying moist but not soggy. Encouraging New Growth on Old Branches: Yes! Light pruning in early spring, just after flowering, can stimulate new growth. Avoid heavy pruning all at once; instead, gradually thin out leggy or unproductive branches over time. Make cuts just above a healthy bud or leaf whorl to encourage branching. Good luck with your rhododendron!
Question
Answer
Fig & Cherry trees
-
Date Posted: Fri, Sep 06 - 11:33 am
- Planted two fig trees (brown Turkey, Hardy Chicago) and a cherry tree (sweetheart) in mid July that have really been struggling recently. I’m wondering what diseases they might have and would love advice on how to treat them. Thank you! Hardy Chicago fig picture attached
- Fig and cherry trees can be a bit sensitive to grow, especially when planted in the heat of summer. The best time to plant is typically in May, or if you are eager to get them in the ground you can plant larger saplings in the fall. Thank you for including the picture, its helpful to see what you are seeing. It's possible the browning you are seeing is related to environmental stress (transplanting, summer heat, etc). However, it also seems likely that your plant is suffering from fig rust, a common issue for fig trees that is caused by a fungal pathogen that can impact the health of the tree if not managed properly. Fig rust symptoms are worse during hot, wet, humid weather in late summer. Fig rust starts out as small, yellowish or reddish spots on the upper side of the leaves. As the disease progresses, these spots may turn brown and become surrounded by a yellow halo. On the underside of the leaves, you may see small, rust-colored pustules, which contain the fungal spores. Fig rust is caused by the fungus Fusicladium effusum. This pathogen thrives in warm, humid conditions and can spread rapidly if the environment is favorable. There are a few things you can do to try to control the fungus from a cultural standpoint that focus on reducing the time that leaves are wet in order to stop spore germination and infection. This includes: avoid overhead irrigation and water at the base of the plant instead, do not plant the trees in shady areas, regularly weed to help keep humidity around the tree lower, and avoid planting in areas that flood or have free-standing water after rainfall. It's also important to remove and destroy any downed leaves from near the plant to remove the fungus.
Question
Answer
Blueberries and Lavender
-
Date Posted: Tue, Aug 27 - 11:37 pm
- Hello, I have 3 questions - I have blueberry bushes that were not properly tended to over the summer heat. They produced lovely berries but since have grown scraggly and I need to trim them back. Is there a proper time and way to do this? I have attempted several times to take cuttings and start new plants. Failed every time. Any suggestions? I have lavender plants in front of the blueberry bushes. They are half alive and half dead. Do I need to move them? I am thinking it is from the overgrowth of limbs from the blueberry bushes but not certain. I am presently in the tedious process of soaking the ground in the evenings and pulling the grass and weeds that surround them. I appreciate your help.
- Thanks for reaching out to the Richmond Master Gardeners! You have several great questions that we will do our best to give you some guidance on: 1. When to prune blueberry bushes: The best time to prune blueberries is in late winter or early spring, just before new growth begins. This timing helps the bush recover and grow new shoots for the coming season. You could also have done some light pruning after harvesting, particularly if you noticed any dead or diseased branches. Regular, light pruning is usually better than infrequent, heavy pruning. Always make clean cuts and avoid leaving stubs, as these can become entry points for pests or diseases. 2. How to prune blueberry bushes: Start by cutting out any dead, damaged, or diseased branches. This helps improve air circulation and reduces the risk of pests and diseases. If the bush is very dense, selectively remove some of the older, thicker branches from the center of the plant to improve airflow and light penetration. This encourages better fruit development. Blueberry bushes produce the most fruit on new growth. Cut back older branches that are more than 6 years old to promote the growth of new, fruitful shoots. Aim for a well-rounded shape, which helps the bush maintain balance and supports better fruit production. Trim to keep the bush to a manageable size and shape, typically removing no more than a third of the plant's height in one season. During the growing season, you can also trim any overly vigorous shoots that might be crowding the plant, encouraging a more balanced structure. 3. Using cuttings to start new plants: The best time to take blueberry cuttings is from late summer to early fall when the wood is semi-hard but not yet fully mature. Choose cuttings from healthy, vigorous plants. Look for shoots that are not too old or too young. Ideally, the cuttings should be from the current season's growth and about 4-6 inches long. If possible, select shoots that haven't flowered, as they will have more energy to put into growing roots. - Preparing Cuttings: Make a clean cut just below a node (the point where leaves attach to the stem). This is where the roots are most likely to develop. Strip off the lower leaves, leaving a few at the top. This reduces moisture loss and encourages root growth. Although optional, dipping the cut end in rooting hormone can improve the chances of successful rooting. Rooting hormone is available in powder, gel, or liquid form. -Planting: Use a well-draining rooting medium like a mix of peat moss and perlite or sand. You can also use a commercial rooting mix. Insert the cuttings into the rooting medium about 1-2 inches deep. Firm the soil around them to ensure good contact. -Care: Keep the rooting medium consistently moist but not waterlogged. Water the cuttings gently to avoid displacing them. Cover the cuttings with a plastic bag or place them in a greenhouse or a propagation chamber to maintain high humidity. Ensure the cover does not touch the cuttings to avoid mold. Place the cuttings in a location with bright, indirect light. Avoid direct sunlight, which can be too intense for young cuttings. -Transplanting: After about 8-12 weeks, check for root development by gently tugging on the cuttings. If you feel resistance, roots have formed. Rooting can take time, so be patient and avoid disturbing the cuttings too soon. Once roots are established, transplant the cuttings into small pots with a potting mix suitable for blueberries or a mix of peat and perlite. Gradually acclimate the young plants to outdoor conditions by exposing them to more light and outdoor temperatures over a couple of weeks. 4. Caring for lavender plants: Lavender plants can be a bit finicky, but several common issues could be causing them to struggle or die. Here are a few things to think about: Lavender needs well-draining soil. Heavy, clayey, or waterlogged soils can lead to root rot. Consider improving drainage by adding sand or gravel to the soil, or planting in raised beds or containers with good drainage. Lavender prefers slightly alkaline to neutral soil, ideally with a pH between 6.7 and 7.3. You can test your soil’s pH with a kit and amend it if necessary. Lavender is drought-tolerant and doesn’t like to sit in wet soil. Water sparingly and allow the soil to dry out between waterings. Overwatering can cause root rot and other issues. While lavender prefers less frequent watering, it still needs some moisture, especially in hot, dry conditions. Ensure it gets enough water during prolonged dry spells. Lavender requires full sun to thrive, which means at least 6-8 hours of direct sunlight each day. If it’s not getting enough light, it can become leggy and weak. Lavender generally prefers temperate climates. Extreme cold or heat can stress the plant Lavender doesn’t need a lot of fertilizer. Fungal diseases like root rot, powdery mildew, and rust can affect lavender. Ensure proper spacing for air circulation and avoid overhead watering to reduce disease risk. Lavender benefits from regular pruning to maintain its shape and health. Prune after flowering to remove spent blooms and encourage new growth. Avoid cutting into old, woody stems, as they may not regenerate. Blueberries and lavender can be successfully planted together, but there are a few things to think about to ensure both plants thrive. Both blueberries and lavender prefer acidic to neutral soil. Blueberries thrive in a pH of 4.5 to 5.5, while lavender prefers a pH of around 6.7 to 7.3. This difference in pH requirements means you’ll need to find a balance or be prepared to amend the soil appropriately. Both plants need full sun to grow well. Ensure they receive at least 6-8 hours of direct sunlight each day. Both plants require well-draining soil. Blueberries are prone to root rot in poorly drained soils, and lavender, though drought-tolerant, also dislikes wet feet. Blueberries need consistent moisture, especially during the growing season, whereas lavender prefers drier conditions and is more tolerant of drought. Overwatering can lead to issues for both plants, so careful watering practices are necessary. We hope this will give you some guidance for moving forward. Happy gardening!
Question
Answer
Browning Dwarf Arborvitae
-
Date Posted: Wed, Oct 11 - 12:47 am
- Dwarf Arborvitae has brown sections, on am effort to cut them out, it appears black underneath. What is happening? Thank you.
- I'm sorry you are having these concerns with your Dwarf Arborvitae. The first thing that comes to my mind is canker. Canker is infected wounds in the branches caused by fungi. Wounds can be caused by pruning, storm damage, cold damage, or excessive wetness. In plants with canker, you will observe yellow to reddish-brown branches in the middle of healthy green branches. Closer to base of the branch you may see slightly sunken, reddish cankers with profusely exuding resin. Black pustule-like fruiting bodies known as pycnidia may be seen breaking through the bark. There is no real treatment for canker stem diseases. The fungus survives in infected bark tissues, so it is best to prune all infected branches about 3-4 inches below the canker area. Spread of the fungus can be minimized by sterilizing any blades used between all cuts with a 10 percent bleach or 70 percent alcohol solution. Try to prevent damage to trees. Stressed and wounded plants are more likely to be infested. It is best to keep dwarf trees as open as possible so that they will dry out after rain. Prune to allow air flow in plants. Clean out leaves from the insides of shrubs. Do not bury plants too deep in mulch. Prune out infected branches and fertilize affected trees if needed. Good luck!!
Question
Answer
Japanese Spirea
-
Date Posted: Tue, Oct 10 - 5:24 pm
- My japanese spirea has large dead sections that I just trimmed back. I don't see any bigs. Any ideas? And should this be cut way back in fall?
- Maintenance pruning for spirea can be done anytime of year and damaged or dead branches should be removed as you see them. When removing these branches, be sure to prune back to a point where the branch is still healthy, or back to the ground if the damage occurs throughout the length of the branch. An overall pruning can be done in late winter, just before new leaves begin to appear. Dwarf varieties (which typically grow 1-3ft tall) can be cut back to 4-6" above the ground. Taller growing varieties can be cut back to 10-12" above the ground. Without more information, it is difficult to say what might be causing the dead sections on your plants. These plants do not require a lot of water, and typically do well on rain water alone unless there is an extreme period of drought. You could monitor your soil to be sure it is draining well and not staying too soggy and moist which could lead to disease issues. One thing to keep in mind about Japanese spirea is that it is a non-native invasive plant. It has small seeds that can last for years in the soil making it very difficult to control. Once Japanese spirea is established outside of its intended areas, it can quickly crowd out native species. Unfortunately, the best control method is to remove existing plants. There is a native spirea that could be considered as a replacement: white meadowsweet (Spiraea alba). I hope this information helps you! Happy gardening!
Question
Answer
Maples for Urban Landscaping?
-
Date Posted: Thu, Sep 28 - 12:43 pm
- I need to replace a diseased Dogwood. I was thinking of a Maple tree but I am concerned of the root system. There are so many varieties of Maple, I don’t know where to start. The new tree would be giving shade to a front porch and two Hydrangeas. Can you give some guidance?
- This is a great question. Generally, maples are known to have shallower root systems, but it can depend a lot on the soil conditions. A few things to think about when you are selecting a tree for this space are if the tree is being planted near sidewalks or a driveway, what your soil conditions are like, the amount of sun or shade it will get, and also to look up for power lines. Red maples are generally faster growers and are also native to our area, but they may have shallower root systems. Japanese maples tend to be slower growing but are not native. Sugar maples are also an option but you would want to be sure to select heat tolerant varieties for the Richmond area. Another alternative is Yellowwood. They have nice big leaves, beautiful form and flowers, tolerate the heat and don't get too big. The University of Illinois Extension has a great tree selector tool that you may also find useful: https://web.extension.illinois.edu/treeselector/search.cfm Good luck!