What is wrong with my American filbert hazelnut plant? - Ask Extension
I have a young American filbert hazelnut plant in my front yard that was planted at the beginning of April this year that is having some issues and lo...
Knowledgebase
What is wrong with my American filbert hazelnut plant? #849322
Asked September 10, 2023, 2:29 PM EDT
I have a young American filbert hazelnut plant in my front yard that was planted at the beginning of April this year that is having some issues and looks unhealthy. These problems include orange/brown leaves, soft branches, losing leaves, and it is not growing (it is only 18 inches tall right now). I planted this plant with another of the same species for cross pollination - the plants are 7 feet from each other in my front yard and get lots of sunlight during the day. The other plant is healthy and approximately 33 inches tall with lots of green leaves. It does have a few (less than 5) leaves that also have the orange/brown leaf issue, but its overwhelmingly healthy. Since planting in April, both plants have been watered deeply, roughly, once a week, it's possible I missed a few weeks earlier in the summer. However, in last 2 months they have been watered more frequently (3-4 times a week) and given them two doses of plant food using this product (https://aerogarden.com/accessories/plant-food/<personal data hidden>.html) (diluted for outdoor plants). In my Google searches before reaching out, it seemed like maybe the issue was a potassium deficiency in the soil so they were given plant food to try and correct the issue, but the struggling plant looks like its losing more and more leaves even with plant food and watering over the last two months. I'm not sure if I need to be more patient as the plant is recovering or if I need to take additional steps to help the plant make it. I'd also like to note that both plants have been in deer cages and I have not noticed damage from deer. I also havent noticed a bug infestation of any kind on the plants. Can you please help me figure out a course of action to help the struggling plant get become healthy?
Howard County Maryland
Expert Response
The symptoms appear to be abiotic (that is, not due to a pest or disease but rather environmental conditions) and it can be normal for plants this recently planted to take a year or so to establish more fully and produce active, lush above-ground growth. (It is presumably still producing root growth for now, even if not generating more branch growth or foliage.) It's also normal for most shrubs to not produce much in the way of new foliage or branch elongation much beyond early summer, since they focus a burst of growth from around April/May into June.
Planting depth may influence how rapidly roots readjust after planting; the junction where roots branch off the main trunk/stem base, called the root flare, should sit just at the soil surface and not be too high or low beneath it. The flare won't look like much on a plant this young and is more prominent on older trees than shrubs, but it's still a physiological feature they all have in common which should lie just at the soil surface for best long-term root health. You won't necessarily have to replant this shrub, but it's something to keep in mind going forward. Hazelnuts and other species that can sucker might not be as reliant on the precision of proper planting depth as single-stemmed shrubs/trees since Hazelnuts can grow new stems from the root zone as they mature, meaning that any of the plant's original stems (if they happened to be placed too deep upon planting) could more easily be replaced by the plant if, at worst, they died back years later.
Missing a few waterings, if the roots got too dry in between irrigation sessions, could certainly cause stress symptoms like the premature fall color and minor amounts of "scorch" (dried margins) visible in the photos. It's not common for shrubs to need routine fertilization, and ideally a laboratory soil test should be used to assess what nutrient levels are like prior to fertilizing so only what's needed is applied. The formulation you used appears to be intended for use in hydroponic setups, though use for in-ground plants is probably harmless. The soil test will also measure acidity (pH), since if this falls outside of a plant's preferred range, the roots may have trouble absorbing the nutrients they need regardless of how abundant they are in the soil. Home test kits exist for basic nutrients and pH, but they are not as accurate or detailed. A potassium deficiency is not common in Maryland soils, though we can't rule it out based on symptoms alone.
Fertilizing plants that are stressed or damaged by insects or pathogens is not recommended in most cases since this can potentially worsen plant stress. It might not be causing overt problems here, but even so, we'd suggest you stop fertilizing at this point. Plus, late in the growing season, shrubs should not need any supplemental nutrients, especially if they are adjacent to lawn that is fertilized at least once a year, since runoff will give them access to those nutrients as well. You can resume in spring or early summer if a soil test shows certain nutrients are lacking in abundance.
We recommend placing a zone of mulch around the base of each Hazelnut instead of allowing the turfgrass to grow that close to the trunk/main stem. Even if you are very careful mowing or trimming the grass so as to not injure the bark (the wound from such cuts can be fatal for young trees/shrubs), the turf is still competing with the Hazelnut roots for moisture and nutrients. By clearing a zone of turf around the base of each plant and protecting the soil with mulch instead, that can help give an establishing plant the edge it needs to overcome competition later. Plus, the mulched zone could be expanded as the shrub matures, along with its deer protection zone. Only a couple inches of mulch in a flat layer would be needed, and keep the mulch from being piled up against the trunk/stem base itself by having a few inches encircling the stem free of mulch.
For now, just keep monitoring the plant for watering needs by feeling the soil around six inches deep next to the root zone. If damp to the touch at that depth when checked, watering should not be needed. If somewhat dry to the touch instead, then watering may help the plant if rain isn't expected soon. Hazelnuts prefer soil that is about average with regards to moisture, meaning they should not stay consistently wet nor get too dry. It's probably more tolerant of mild drought than it is excessive moisture, but overall it's considered to be fairly flexible (once established for a few years, that is). Watering three or four times per week sounds higher than should be necessary, so maybe back it off to once or maybe twice a week, based on what probing the soil by touch or with a trowel suggests as far as how damp or dry it is at that six-inch depth. You might find that even once a week is plenty based on how the soil there is retaining moisture. Overall, considering we're near the end of the growing season, the plant doesn't look too bad, and we think it will leaf-out normally next spring.
Miri
Planting depth may influence how rapidly roots readjust after planting; the junction where roots branch off the main trunk/stem base, called the root flare, should sit just at the soil surface and not be too high or low beneath it. The flare won't look like much on a plant this young and is more prominent on older trees than shrubs, but it's still a physiological feature they all have in common which should lie just at the soil surface for best long-term root health. You won't necessarily have to replant this shrub, but it's something to keep in mind going forward. Hazelnuts and other species that can sucker might not be as reliant on the precision of proper planting depth as single-stemmed shrubs/trees since Hazelnuts can grow new stems from the root zone as they mature, meaning that any of the plant's original stems (if they happened to be placed too deep upon planting) could more easily be replaced by the plant if, at worst, they died back years later.
Missing a few waterings, if the roots got too dry in between irrigation sessions, could certainly cause stress symptoms like the premature fall color and minor amounts of "scorch" (dried margins) visible in the photos. It's not common for shrubs to need routine fertilization, and ideally a laboratory soil test should be used to assess what nutrient levels are like prior to fertilizing so only what's needed is applied. The formulation you used appears to be intended for use in hydroponic setups, though use for in-ground plants is probably harmless. The soil test will also measure acidity (pH), since if this falls outside of a plant's preferred range, the roots may have trouble absorbing the nutrients they need regardless of how abundant they are in the soil. Home test kits exist for basic nutrients and pH, but they are not as accurate or detailed. A potassium deficiency is not common in Maryland soils, though we can't rule it out based on symptoms alone.
Fertilizing plants that are stressed or damaged by insects or pathogens is not recommended in most cases since this can potentially worsen plant stress. It might not be causing overt problems here, but even so, we'd suggest you stop fertilizing at this point. Plus, late in the growing season, shrubs should not need any supplemental nutrients, especially if they are adjacent to lawn that is fertilized at least once a year, since runoff will give them access to those nutrients as well. You can resume in spring or early summer if a soil test shows certain nutrients are lacking in abundance.
We recommend placing a zone of mulch around the base of each Hazelnut instead of allowing the turfgrass to grow that close to the trunk/main stem. Even if you are very careful mowing or trimming the grass so as to not injure the bark (the wound from such cuts can be fatal for young trees/shrubs), the turf is still competing with the Hazelnut roots for moisture and nutrients. By clearing a zone of turf around the base of each plant and protecting the soil with mulch instead, that can help give an establishing plant the edge it needs to overcome competition later. Plus, the mulched zone could be expanded as the shrub matures, along with its deer protection zone. Only a couple inches of mulch in a flat layer would be needed, and keep the mulch from being piled up against the trunk/stem base itself by having a few inches encircling the stem free of mulch.
For now, just keep monitoring the plant for watering needs by feeling the soil around six inches deep next to the root zone. If damp to the touch at that depth when checked, watering should not be needed. If somewhat dry to the touch instead, then watering may help the plant if rain isn't expected soon. Hazelnuts prefer soil that is about average with regards to moisture, meaning they should not stay consistently wet nor get too dry. It's probably more tolerant of mild drought than it is excessive moisture, but overall it's considered to be fairly flexible (once established for a few years, that is). Watering three or four times per week sounds higher than should be necessary, so maybe back it off to once or maybe twice a week, based on what probing the soil by touch or with a trowel suggests as far as how damp or dry it is at that six-inch depth. You might find that even once a week is plenty based on how the soil there is retaining moisture. Overall, considering we're near the end of the growing season, the plant doesn't look too bad, and we think it will leaf-out normally next spring.
Miri
