Question: We just planted (3 months ago) a beautiful camphora tree (15'' gal - about 1.5" trunk diameter +/- 7 feet tall). Recently, I have noticed new leaves starting to come out; but MANY leaves (old?) start to curl and get dark-brown at the tips. Is the tree "sick" or getting sick?
Lately we have had strong winds which have broken many small branches/leaves. Some leaves have irregular holes on them (insects? pests?). Where could we find more information on how to identify problems with this and other trees/plants?
Also, regarding watering, this tree is getting water from a sprinkler system which waters shrubs as follows: 3 times a week for about 3 minutes in the early morning only. Is this good enough? How do I provide deep watering for this and other trees? How could I test if the tree has adequate water? The soil retains water (clay)- slow drainage.
Answer: Camphor trees
are generally robust street trees, but they can develop a fungal disease (verticillium wilt) in clayey, poorly draining soils. The symptoms you describe could be the beginning of a disease or simply be indications of transplant stress or inadequate watering practices.
Cinnamomum camphora grows best in full sunshine, in slightly acidic, well-draining soils. Watering every other day for 3 minutes might wet the soil surface, but the volumne isn't enough to wet the entire root system. It would be better for your tree if you placed a sprinkler beneath the canopy and watered for 15-20 minutes once each week. This will apply enough water at a slow enough rate to allow the moisture to trickle down and wet the entire rootmass. Excessive leaf drop is a classic symptom of verticillium wilt. If your tree is shedding older leaves only, then it's a natural process and new foliage will develop soon. If your tree is dropping both old and new leaves, I'd suspect a root problem - possibly verticillium wilt. This soil-borne fungus grows during the winter in poorly drained, cool soil, attacks a plant's vascular system and results in excessive leaf drop and dead branches. It can ultimately kill the tree.
To improve the health of your trees, change your irrigation practices. If you have turf under the trees, consider replacing it with a drought-tolerant ground cover, bark or gravel. Moderate applications of slow-release nitrogen fertilizer during the growing season will promote new growth and improve your tree's chance for survival.
Insect pests don't often attack the foliage of camphor trees so the holes you see may be from wind damage, not from pests. Your local Cooperative Extension office will have information on plant problems. Some publications are free and others are offered for a nominal fee. Phone 714-708-1606 for information about plant care publications.
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