Salt wind can damage plants

Aloha, Mr. Sakovich. First, let me thank you for all the assistance you provide to the gardeners here and for your classes at the University of Hawaii at Hilo.

I live on 2nd Avenue in Hawaiian Paradise Park, close to Kaloli Point.

I planted a number of trees three years ago, and my avocado tree was doing really well up until about five months ago when the leaves started turning brown and falling off. I cannot see any surface insects, so is this a root problem and is the tree a goner?

I also have two star fruit trees that I planted at the same time, and for the second year I had plenty of fruit, even though the trees are only 3 feet tall. Now, nothing. Thanks for the ongoing support. — Mahalo, M.B.

The area you live in certainly presents challenges for growing many plants. If the leaves are browning from the tip back or around the margins, this is typical salt burn.

This symptom can be caused by salts from the ocean spray collecting on the foliage and in the root zone.

In addition, over fertilization will contribute to salts in the soil. This may be the problem since avocados are sensitive to these conditions. If that’s the case, planting another type of tree would be the solution.

Incidentally, avocados are also susceptible to root rot, usually when over watered or where there is poor drainage; yet, this probably is not the problem. Furthermore, at times a tree will drop its leaves in response to unknown adverse conditions. Under this circumstance, a new flush of growth may soon appear indicating the tree is in recovery.

Concerning the carambola, or starfruit, although they will grow in a wide variety of soils, they also have a low salt tolerance. A report from the Caribbean mentions that carambolas are well suited for light shade or full sun but have poor salt tolerance and should be kept away from a direct salt wind.

For a list of plants tolerant to salt and wind, consult the CTAHR publication, “Salt and Wind Tolerance of Landscape Plants for Hawai‘i.”

I purchased a hyacinth flower at the store. I would like to know if once it is finished flowering, I can plant it out in my garden. Will it bloom for me next year? I live in Glenwood where it does get cold.

Hyacinths (Hyacinthus orientalis and its hybrids) are in the lily family, planted as bulbs and known for their beautiful, fragrant flowers.

They do well in cold climates; they are not a tropical plant. Even garden books note that they can be grown in all zones except Hawaii. In areas of the country with distinct cold winters, bulbs can be left in the ground and with proper chilling, will bloom the next year.

The Roman or French hyacinth is native to Southern France and can remain in the ground year after year in areas of little or no winter chill — but not Hawaii.

Here’s one thing you can try: after the bloom has died, put the bulb with its leaves in the ground. The leaves should eventually yellow and dieback. At this point, dig up the bulb, set it in a small pot with potting soil, cover to keep dark, also keep soil moist. Place in the refrigerator, it must be below 45 degrees Fahrenheit and remain there for at least 10 weeks. Roots will grow and eventually a shoot tip will emerge. At this point, it can be removed from the refrigerator. This is a lot of effort and no guarantee it will work; hyacinths are just one of those plants that has to be purchased each year.

Class Announcement

It’s not too late to sign up for the vegetable gardening class I am teaching from 9:30 a.m.-12 p.m. Saturday, April 20, at the University of Hawaii at Hilo campus. Call 974-7664 to register, or go online at http://hilo.hawaii.edu/academics/ccecs/fitness/. There is a fee.

Hilo resident Nick Sakovich is a professor emeritus of the University of California. He has worked in the field of agriculture for 30 years. Email your questions to Sakovich at askthegardenguy@earthlink.net.