Stressed Redbud Tree - Ask Extension
Can this redbud tree be saved? The 2012 derecho split this tree, but on the advice of the landscape service, we kept it to see if it would survive. It...
Knowledgebase
Stressed Redbud Tree #849492
Asked September 11, 2023, 3:56 PM EDT
Can this redbud tree be saved? The 2012 derecho split this tree, but on the advice of the landscape service, we kept it to see if it would survive. It has done remarkably well until last summer, when the seed pods appeared on the tree much earlier than usual. This year it is already dropping leaves, has many dark brown seed pods and seems to be stressed from the drought. The area where the tree is located (in an over-55 community in Glenwood) was treated last year for moles/voles. It was treated about a month ago with an annual fertilizer and herbicide treatment, and then about two weeks ago the area was treated for Japanese stilt grass. We love this tree and don't want to remove it if we can save it. There are four thriving redbud trees in front of our quad that show none of these signs of stress. We wondered if this treatment that we found on a website would help: https://www.treehelp.com/products/treehelp-annual-care-kit-redbud.
Howard County Maryland
Expert Response
This will be a long answer, but we'll be addressing a few different topics contributing to situations like this.
The foliage doesn't look too bad and the abundance of seed pods by itself isn't necessarily concerning, though it is true that sometimes stressed plants can produce more seed if they are in decline. What would help, both for this individual and for any other tree now (like those other Redbuds) or in the future, is to surround its trunk with a zone of mulch instead of allowing the turfgrass to grow immediately next to it, and to irrigate as needed depending on weather (if possible).
Mulch helps protect trunks from bark damage due to mowers, weed whackers, or bark-absorbed herbicide applications, plus helps to keep the grass further away from the young tree's root system to minimize competition for moisture and nutrients. Mulch should be used upon planting to give a tree a good start, but adding it after the fact can still help reduce future struggles. Make sure mulch does not cover any bark and keep it in a flat layer (so, no "volcano" mounds that are typical of poorly-trained landscapers).
It's hard to tell from the photos, but we think we see a constricted zone at the very base of the trunk, which suggests prior and repetitive damage from lawn equipment. Wounds from this kind of injury are serious if they cut into the live tissue just underneath the bark, which can either die outright from the damage or become colonized by wood-decay organisms. Neither condition can be treated, though if damage is minor, a tree might be able to gradually repair it by sealing-off the wound over time. No coating or sealant of any type should be applied to that or any other tree wound as it might hamper that "healing" process or trap wood-decay organisms inside the wood instead of keeping them out.
With regards to irrigation, drought stress can tax even the most drought-tolerant of plants (Redbud not being among those), and young or still-establishing trees only a few years out from planting are among the most vulnerable. Even so, competition between tree roots and lawn will be a long-term issue when trees are grown amid turf, and although lawn irrigation can benefit trees, lawns are not always watered to keep them vigorous or in active growth. (By itself, this is not necessarily a problem for the turf if soil drying is not severe. It's normal for cool-season lawns like fescue to go somewhat dormant during summer to escape the heat and drier weather.) Trees don't always show signs of stress right away, though, so might not indicate they could use attention until a problem is more advanced, when it is more likely to have already caused some longer-term damage or made the plant more vulnerable to attack by pests or diseases.
To determine when to irrigate, monitor plants for watering needs by feeling the soil about six inches deep into the root zone. If damp to the touch at that depth when checked, watering is probably not necessary yet. If instead the soil is becoming somewhat dry to the touch at that depth, then a thorough watering will probably be beneficial, even if foliage isn't yet wilting, scorching, yellowing, or shedding. Immature trees tend to need at least around 20 gallons (as a generalized frame of reference) per tree per watering session to fully rehydrate the root ball and surrounding soil. About an inch of rain (including any irrigation water) is the recommended watering amount per week, at least in warm weather during the growing season. You may find that, depending on soil type and its degree of compaction, some plants won't need watering that often in dry weather, or others may need it more often. Redbuds fall in the middle ground: they are not very tolerant of consistently-soggy or poorly-drained soil, nor do they want to get too dry between waterings. With practice, the soil probing technique mentioned above might not be needed each time you're wondering if watering would be helpful or if it can wait, since you'll be accustomed to how readily (or not) the soil dries out to the point of intervention when rains are lacking.
If using a handheld hose nozzle, sprinkler, or other system to water is impractical or cost-prohibitive, one solution can be to use either a purchased tree-watering bag (a common capacity is 20 gallons) or a standard 5-gallon plastic bucket with small holes drilled in its base to hold and slowly drip water into the tree's root zone. The bag stays in place, refilled as needed, but the bucket would need to be filled a few times because of its smaller capacity and just moved each time to drip into a different area encircling the tree to more evenly wet most of the root zone. Either of these containers not only allow you to keep track of how much water you're applying each time, but also applies it slowly enough that it's less likely to run off to areas not deemed a priority.
This year's drought might impact trees for the next several years if symptoms of damage weren't more immediate. Drought stress, plus other stresses, can also predispose some plants to infection by opportunistic fungi, which include canker-causing organisms like Botryosphaeria. Redbud trees can fall victim to this fungus. There are no fungicides to cure such infections, so the best approach is prevention, in the form of keeping plants as stress-free as possible by managing irrigation needs proactively. Trees and other plants being irrigated should be monitored until the ground starts to freeze since we have experienced abnormally-dry autumn spells in years past, with consequences for long-term plant health. Premature leaf shed is a typical reaction to drought stress and we've seen several moisture-loving tree species around our area forests already starting to shed leaves, even with recent rains. (Once that stress response starts, yellowed leaves will not green-up again and remain attached, though if no other damage was done, those branches should leaf-out normally the following spring.)
We weren't clear about whether the fertilizer + herbicide treatment you mentioned was applied to the lawn or another area. (We assume the lawn.) Any tree roots growing into a nearby lawn (all of them in this situation) will have access to those nutrients and should not need any more. (They don't even need those, usually, but lawn fertilizer amounts should be plenty by itself.) Therefore, products like the one you linked to, which provide even more nutrient supplementation, are likely overkill and are neither needed by the tree nor helpful in alleviating any of its stress. In fact, for plants experiencing drought stress or other issues (pests or diseases), fertilization might worsen a plant's condition. Rarely is soil nutrient deficiency bad enough that supplementation with fertilizer is going to be necessary, at least not regularly. Hopefully any herbicide applied to the lawn is either kept away from the trees or selected with caution so the active ingredient is not at risk of being absorbed into tree roots.
As for the other components of that kit, mycorrhizae and a biostimulant, these are also not necessary and probably provide little to no benefit. Mycorrhizae are diverse and are a required (or at least very important) fungal partner for the majority of plant species, helping them absorb moisture and nutrients by growing in close association with roots and taking a few of the tree's carbohydrate stores (but not too much) in return; the fungus and plant rely on each other to function better as a team, and each benefits from that relationship. However, soils that are not in very poor shape already have plenty of mycorrhizal species and other beneficial microbes living within them, especially if occasionally supplemented with organic material that feeds these microbes as it decays, like compost, grass clippings left to degrade on the lawn (via a mulching mower instead of one that bags-up clippings), and bark mulches. While adding more mycorrhizae might not hurt, we have no scientific evidence that this boost actually supports plant health since plenty already exist around the plant's roots. (It would be a bit like adding fertilizer when the soil is already sufficiently nutrient-rich.) We also don't know how well mycorrhizae tolerate storage in the manufacturing process so have no way to tell how many in a packaged mix are still alive and viable. Biostimulant ingredients similarly might have real-world benefits to plant roots when they occur naturally, such as being a byproduct of this microbial activity in healthy soil, but as an additive also have no reliable scientific support. You can skip them both.
To circle back to your question of whether the tree can be saved, we can't really predict that based on how the tree looks now, but the information shared above will hopefully let you assess how actions can help give the tree its best chance at recovery, or at least how to set up a replacement tree for success. Redbuds are pioneer species -- they readily seed-into disturbed areas that might have less-than-ideal soil conditions and live faster, shorter lives than their forest-canopy counterparts like sycamore and oak. They can also surprise us, though, and even a tree losing branches to Botryosphaeria or drought damage might still be able to regrow from roots if you don't mind a more drastic process of removal of lots of dead wood and waiting for new trunks (usually several) to be produced by root sprouts (suckers). In that way, a tree might rebound for a second lifespan, so to speak, as long as its root system is robust enough. Since most gardeners don't want to wait several more years to single-out one trunk to keep (or don't want that shrubbier, multi-trunked look while the tree matures again), sometimes it's simpler to just replace a tree in that degree of decline. That's a cost-benefit assessment that only you can do since neither option is right or wrong. Autumn is an excellent time to plant trees, though spring is fine as well.
Miri
The foliage doesn't look too bad and the abundance of seed pods by itself isn't necessarily concerning, though it is true that sometimes stressed plants can produce more seed if they are in decline. What would help, both for this individual and for any other tree now (like those other Redbuds) or in the future, is to surround its trunk with a zone of mulch instead of allowing the turfgrass to grow immediately next to it, and to irrigate as needed depending on weather (if possible).
Mulch helps protect trunks from bark damage due to mowers, weed whackers, or bark-absorbed herbicide applications, plus helps to keep the grass further away from the young tree's root system to minimize competition for moisture and nutrients. Mulch should be used upon planting to give a tree a good start, but adding it after the fact can still help reduce future struggles. Make sure mulch does not cover any bark and keep it in a flat layer (so, no "volcano" mounds that are typical of poorly-trained landscapers).
It's hard to tell from the photos, but we think we see a constricted zone at the very base of the trunk, which suggests prior and repetitive damage from lawn equipment. Wounds from this kind of injury are serious if they cut into the live tissue just underneath the bark, which can either die outright from the damage or become colonized by wood-decay organisms. Neither condition can be treated, though if damage is minor, a tree might be able to gradually repair it by sealing-off the wound over time. No coating or sealant of any type should be applied to that or any other tree wound as it might hamper that "healing" process or trap wood-decay organisms inside the wood instead of keeping them out.
With regards to irrigation, drought stress can tax even the most drought-tolerant of plants (Redbud not being among those), and young or still-establishing trees only a few years out from planting are among the most vulnerable. Even so, competition between tree roots and lawn will be a long-term issue when trees are grown amid turf, and although lawn irrigation can benefit trees, lawns are not always watered to keep them vigorous or in active growth. (By itself, this is not necessarily a problem for the turf if soil drying is not severe. It's normal for cool-season lawns like fescue to go somewhat dormant during summer to escape the heat and drier weather.) Trees don't always show signs of stress right away, though, so might not indicate they could use attention until a problem is more advanced, when it is more likely to have already caused some longer-term damage or made the plant more vulnerable to attack by pests or diseases.
To determine when to irrigate, monitor plants for watering needs by feeling the soil about six inches deep into the root zone. If damp to the touch at that depth when checked, watering is probably not necessary yet. If instead the soil is becoming somewhat dry to the touch at that depth, then a thorough watering will probably be beneficial, even if foliage isn't yet wilting, scorching, yellowing, or shedding. Immature trees tend to need at least around 20 gallons (as a generalized frame of reference) per tree per watering session to fully rehydrate the root ball and surrounding soil. About an inch of rain (including any irrigation water) is the recommended watering amount per week, at least in warm weather during the growing season. You may find that, depending on soil type and its degree of compaction, some plants won't need watering that often in dry weather, or others may need it more often. Redbuds fall in the middle ground: they are not very tolerant of consistently-soggy or poorly-drained soil, nor do they want to get too dry between waterings. With practice, the soil probing technique mentioned above might not be needed each time you're wondering if watering would be helpful or if it can wait, since you'll be accustomed to how readily (or not) the soil dries out to the point of intervention when rains are lacking.
If using a handheld hose nozzle, sprinkler, or other system to water is impractical or cost-prohibitive, one solution can be to use either a purchased tree-watering bag (a common capacity is 20 gallons) or a standard 5-gallon plastic bucket with small holes drilled in its base to hold and slowly drip water into the tree's root zone. The bag stays in place, refilled as needed, but the bucket would need to be filled a few times because of its smaller capacity and just moved each time to drip into a different area encircling the tree to more evenly wet most of the root zone. Either of these containers not only allow you to keep track of how much water you're applying each time, but also applies it slowly enough that it's less likely to run off to areas not deemed a priority.
This year's drought might impact trees for the next several years if symptoms of damage weren't more immediate. Drought stress, plus other stresses, can also predispose some plants to infection by opportunistic fungi, which include canker-causing organisms like Botryosphaeria. Redbud trees can fall victim to this fungus. There are no fungicides to cure such infections, so the best approach is prevention, in the form of keeping plants as stress-free as possible by managing irrigation needs proactively. Trees and other plants being irrigated should be monitored until the ground starts to freeze since we have experienced abnormally-dry autumn spells in years past, with consequences for long-term plant health. Premature leaf shed is a typical reaction to drought stress and we've seen several moisture-loving tree species around our area forests already starting to shed leaves, even with recent rains. (Once that stress response starts, yellowed leaves will not green-up again and remain attached, though if no other damage was done, those branches should leaf-out normally the following spring.)
We weren't clear about whether the fertilizer + herbicide treatment you mentioned was applied to the lawn or another area. (We assume the lawn.) Any tree roots growing into a nearby lawn (all of them in this situation) will have access to those nutrients and should not need any more. (They don't even need those, usually, but lawn fertilizer amounts should be plenty by itself.) Therefore, products like the one you linked to, which provide even more nutrient supplementation, are likely overkill and are neither needed by the tree nor helpful in alleviating any of its stress. In fact, for plants experiencing drought stress or other issues (pests or diseases), fertilization might worsen a plant's condition. Rarely is soil nutrient deficiency bad enough that supplementation with fertilizer is going to be necessary, at least not regularly. Hopefully any herbicide applied to the lawn is either kept away from the trees or selected with caution so the active ingredient is not at risk of being absorbed into tree roots.
As for the other components of that kit, mycorrhizae and a biostimulant, these are also not necessary and probably provide little to no benefit. Mycorrhizae are diverse and are a required (or at least very important) fungal partner for the majority of plant species, helping them absorb moisture and nutrients by growing in close association with roots and taking a few of the tree's carbohydrate stores (but not too much) in return; the fungus and plant rely on each other to function better as a team, and each benefits from that relationship. However, soils that are not in very poor shape already have plenty of mycorrhizal species and other beneficial microbes living within them, especially if occasionally supplemented with organic material that feeds these microbes as it decays, like compost, grass clippings left to degrade on the lawn (via a mulching mower instead of one that bags-up clippings), and bark mulches. While adding more mycorrhizae might not hurt, we have no scientific evidence that this boost actually supports plant health since plenty already exist around the plant's roots. (It would be a bit like adding fertilizer when the soil is already sufficiently nutrient-rich.) We also don't know how well mycorrhizae tolerate storage in the manufacturing process so have no way to tell how many in a packaged mix are still alive and viable. Biostimulant ingredients similarly might have real-world benefits to plant roots when they occur naturally, such as being a byproduct of this microbial activity in healthy soil, but as an additive also have no reliable scientific support. You can skip them both.
To circle back to your question of whether the tree can be saved, we can't really predict that based on how the tree looks now, but the information shared above will hopefully let you assess how actions can help give the tree its best chance at recovery, or at least how to set up a replacement tree for success. Redbuds are pioneer species -- they readily seed-into disturbed areas that might have less-than-ideal soil conditions and live faster, shorter lives than their forest-canopy counterparts like sycamore and oak. They can also surprise us, though, and even a tree losing branches to Botryosphaeria or drought damage might still be able to regrow from roots if you don't mind a more drastic process of removal of lots of dead wood and waiting for new trunks (usually several) to be produced by root sprouts (suckers). In that way, a tree might rebound for a second lifespan, so to speak, as long as its root system is robust enough. Since most gardeners don't want to wait several more years to single-out one trunk to keep (or don't want that shrubbier, multi-trunked look while the tree matures again), sometimes it's simpler to just replace a tree in that degree of decline. That's a cost-benefit assessment that only you can do since neither option is right or wrong. Autumn is an excellent time to plant trees, though spring is fine as well.
Miri
Miri, thank you so much for such a clear and detailed response. The tree was originally one of the free trees offered by Howard County, and we lost entirely half of it in the Derecho and were surprised that it survived. Your answer makes a lot of sense, since the four redbuds in front of our quad are all in the mulch beds.
We'll take a closer look at the trunk at the bottom, and if the weed whacker hasn't damaged the live tissue, we'll mulch it and see how it doesn next year. If not, we'll replace it and follow the guidelines you suggested.
I really appreciate the Extension's services over the years. I served as chair of the Landscaping Committee a few years ago and often asked questions that were answered in a way that saved our community money. You guys are the best!
You're very welcome!
I would add one reference resource for future plantings, then, having planted one of those trees myself in recent years: explore our Planting a Tree or Shrub web page, since it discusses the importance of placing a tree's root flare at the right depth. (The root flare is the juncture of major roots with the trunk base, where they will eventually widen in a more obvious "flare" as they mature.) Many nursery-grown trees have their root flare buried by several inches of soil by the time they are sold, and correcting this depth upon planting, so the flare sits at the soil surface, is important to avoid issues with girdling roots and other long-term damage as the tree matures.
I have also found that even trees with a flare at the proper depth have surprisingly bent or twisted main roots at the heart of the root ball that would not be evident if the soil wasn't rinsed away prior to planting to investigate; a result from younger pot sizes as the tree was bumped-up into larger containers as it grew, where roots didn't have enough space in time to avoid getting kinked. Such roots run the risk of compromising tree health if not corrected or pruned out (within reason) prior to planting. If partially bare-rooting a tree in this manner, use a wheelbarrow or large bucket to keep the exposed roots from getting too dry; you can then use the collected spray water to water the tree in after planting so it's not wasted. If a landscape contractor does the planting instead of anyone living on-site, then try to see if they are trained in proper tree planting techniques prior to installation so you can be assured efforts were made to give the tree the best start possible. Avoiding any root structural issues isn't always possible, unfortunately, but at least proper planting won't compound the problem over time.
Miri
I would add one reference resource for future plantings, then, having planted one of those trees myself in recent years: explore our Planting a Tree or Shrub web page, since it discusses the importance of placing a tree's root flare at the right depth. (The root flare is the juncture of major roots with the trunk base, where they will eventually widen in a more obvious "flare" as they mature.) Many nursery-grown trees have their root flare buried by several inches of soil by the time they are sold, and correcting this depth upon planting, so the flare sits at the soil surface, is important to avoid issues with girdling roots and other long-term damage as the tree matures.
I have also found that even trees with a flare at the proper depth have surprisingly bent or twisted main roots at the heart of the root ball that would not be evident if the soil wasn't rinsed away prior to planting to investigate; a result from younger pot sizes as the tree was bumped-up into larger containers as it grew, where roots didn't have enough space in time to avoid getting kinked. Such roots run the risk of compromising tree health if not corrected or pruned out (within reason) prior to planting. If partially bare-rooting a tree in this manner, use a wheelbarrow or large bucket to keep the exposed roots from getting too dry; you can then use the collected spray water to water the tree in after planting so it's not wasted. If a landscape contractor does the planting instead of anyone living on-site, then try to see if they are trained in proper tree planting techniques prior to installation so you can be assured efforts were made to give the tree the best start possible. Avoiding any root structural issues isn't always possible, unfortunately, but at least proper planting won't compound the problem over time.
Miri
