Creeping Juniper Drought Damage
Rich has some creeping juniper with excessive browning. The branches are mostly green on the ends and the needles seem to fall from the inner portions. The junipers overhang rocks and receive full sunlight. The soil is mostly sandy. There appears to be new growth with no visible bugs on the branches. During late winter, the deer were eating some of the nearby junipers and he applied both Liquid Fence (for the deer) and Miracid via watering can in attempts to clear up the browning. He wants to know if he should attempt any pruning, or use Miracle-Gro or Miracid on the junipers. Should he be watering the junipers during dry spells? Rich also provided excellent photos, which were very helpful in the diagnosis of his problem.
The growing site, full sun, sandy soil, is ideal for creeping juniper. For this reason it is unlikely you have a fungal disease. Phomopsis and Kabatina blight are a problem when the growing location is moist, and they affect new growth. Also, no lesions are visible in the close-up photos provided. You can confirm this by looking for ashen-grey, sunken lesions at the junction of healthy and browned tissue.
My conclusion is the excessive areas of browning were caused by last year’s drought. Creeping juniper is drought tolerant, but last year the drought was quite severe and lengthy. The snow cover would have provided protection, but the roots would not have been able to absorb moisture once the ground had frozen.
Junipers put on new growth only from the ends of the branches, so pruning back to a bare area will not produce new growth. You can certainly trim out the browned branches to improve the appearance. Branches that are almost entirely bare should be removed to allow nearly branches to fill in the space.
Wait until fall to fertilize. This is when the roots are actively taking up nutrients. Plants take in few nutrients when the new shoots are actively growing. You want fertilizer to get to the roots and not remain on the needles where the salts can burn, so if using a liquid fertilizer, apply it before rain is expected, or spray with clear water afterwards. Since your location is on the water you want to use a fertilizer with little or no phosphorous such as 10-0-0 or 24-8-16. Junipers grow in a wide range of soil pH and do not need acid supplementation.
It is a good idea to water even drought tolerant plants during extended dry spells. It is especially important that the soil is moist in the fall so the roots can take up nutrients to take the plant through the winter. It is always best to trickle water at the roots rather than spray from above.
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