dying cypress - Ask Extension
Hi, my five 25 foot trees are dying. Half of the tree is already dead. Bartlett's tree service said it was because of the soil but I live on 9 acres...
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dying cypress #875646
Asked July 02, 2024, 12:08 PM EDT
Hi, my five 25 foot trees are dying. Half of the tree is already dead. Bartlett's tree service said it was because of the soil but I live on 9 acres, and other trees are fine. A man at the La Plata Courthouse farmer's market said it sounded like "cedar rust" which I googled and it does look like it except for the "apple" part. Please, is there anything I can do to save these trees?
Charles County Maryland
Expert Response
The plant pictured looks like either a Leyland Cypress (botanical name Cypressocyparis leylandii) or an Eastern Redcedar (Juniperus virginiana). We can't see the foliage clearly enough to be certain, but are leaning towards Leyland Cypress. (You do call it a cypress, but sometimes gardeners use one term for several kinds of evergreens that are not related, and plant ID matters for the diseases in question in this case.)
Cedar-Apple Rust (and related types, like Cedar-Hawthorn, etc.) infect junipers as part of their life cycle, but not Leylands. We agree this does not look like symptoms of rust. Instead, it is consistent with the type of dieback commonly experienced by Leyland Cypress, which can have several causes -- some due to the growing environment and its stresses, some from plant diseases. The most common infections Leylands contract are Seiridium and Botryosphaeria cankers. The linked page provides more information, but essentially these fungi take advantage of trees under stress, even if there are few outward signs of that stress. Drought is a typical cause of stress, especially in soils that drain very quickly (such as sandier soils). Most of 2023 was a drought year for much of Maryland, and so far, 2024 is also significantly short on rainfall (including Charles County). We realize it might not be practical or feasible to irrigate these trees in those circumstances, but it unfortunately predisposes these trees to these infections, which are not curable.
Given the tree's current appearance, it would be most practical to have it removed and replaced. There is no way to regain its former dense foliage and even branching given the degree of dieback that has accumulated. The tree service's comment about the soil potentially being a factor might have been referring to the fact that Leylands are notorious for not developing sturdy or extensive root systems when growing in compacted or heavy clay soil. In our experience though, they tend to do better in that regard when growing in the sandier soils of eastern or southern Maryland. Perhaps they thought the soil was either too dry due to sharp drainage or too wet (when the weather is wet, at least) due to compacted or low-lying conditions.
Regardless of the exact factors contributing to demise, Leylands tend to not live very long in Maryland conditions, and while they can grow taller than 25 feet high, sometimes they struggle to reach that age. Depending on the growing conditions, other evergreens (if you prefer to replace them with something evergreen) may be suitable for that site. If you want to keep the trees for now, all dead growth (whether leafless or brown) should be pruned off, and the root zones may benefit from occasional irrigation if our pattern of insufficient rainfall continues.
Miri
Cedar-Apple Rust (and related types, like Cedar-Hawthorn, etc.) infect junipers as part of their life cycle, but not Leylands. We agree this does not look like symptoms of rust. Instead, it is consistent with the type of dieback commonly experienced by Leyland Cypress, which can have several causes -- some due to the growing environment and its stresses, some from plant diseases. The most common infections Leylands contract are Seiridium and Botryosphaeria cankers. The linked page provides more information, but essentially these fungi take advantage of trees under stress, even if there are few outward signs of that stress. Drought is a typical cause of stress, especially in soils that drain very quickly (such as sandier soils). Most of 2023 was a drought year for much of Maryland, and so far, 2024 is also significantly short on rainfall (including Charles County). We realize it might not be practical or feasible to irrigate these trees in those circumstances, but it unfortunately predisposes these trees to these infections, which are not curable.
Given the tree's current appearance, it would be most practical to have it removed and replaced. There is no way to regain its former dense foliage and even branching given the degree of dieback that has accumulated. The tree service's comment about the soil potentially being a factor might have been referring to the fact that Leylands are notorious for not developing sturdy or extensive root systems when growing in compacted or heavy clay soil. In our experience though, they tend to do better in that regard when growing in the sandier soils of eastern or southern Maryland. Perhaps they thought the soil was either too dry due to sharp drainage or too wet (when the weather is wet, at least) due to compacted or low-lying conditions.
Regardless of the exact factors contributing to demise, Leylands tend to not live very long in Maryland conditions, and while they can grow taller than 25 feet high, sometimes they struggle to reach that age. Depending on the growing conditions, other evergreens (if you prefer to replace them with something evergreen) may be suitable for that site. If you want to keep the trees for now, all dead growth (whether leafless or brown) should be pruned off, and the root zones may benefit from occasional irrigation if our pattern of insufficient rainfall continues.
Miri
Thank you. They are Leyland cypress. I won’t be able to prune all the dead growth. Is it okay to just let it die naturally? There are some 2 foot high American sycamore shoots nearby that I will let grow and hopefully replace the Leyland’s. Thank you again for the information.
You're welcome.
Yes, if they are not an aesthetic issue or obstacle if left as-is to die completely (eventually), there is no harm in not having them cut down. Birds may enjoy perching on the branches, for example. Sycamore can be fast-growing, so will probably cover-up their bare branches in just a few years.
Miri
Yes, if they are not an aesthetic issue or obstacle if left as-is to die completely (eventually), there is no harm in not having them cut down. Birds may enjoy perching on the branches, for example. Sycamore can be fast-growing, so will probably cover-up their bare branches in just a few years.
Miri
