Newly transplanted hibiscus problems

I have an indoor hibiscus that I've had for about 4 years. It is now about 2 feet tall and 3 feet wide. I recently repotted the plant because it had outgrown its pot. It was the first time I've ever repotted it. In the past, the plant has occasionally developed a few yellow leaves. Now I am picking off at least a dozen yellow leaves EACH DAY. In addition to the yellowing, when the leaves are backlit you can see that there is a dramatic spotting of the leaves that appears to be "inside" the leaf. If you look at the leaf from the top or bottom and out of the light, you can see a few small, faint variations in color but the leaves mostly appear normal. One of the branches is nearly leafless now, and even some of the new leaves coming in are yellow. Despite this, the plant is in bloom and has 13 more blooms in various stages of development. I am completely baffled about what is causing this. It is my favorite plant, and I am desperate to remedy whatever problem it is experiencing!

Diane P.

Santa Fe, NM

Growing tropical hibiscus in New Mexico, especially Northern New Mexico, can be a challenge. Our environment is quite different from the humid tropics with organic soils where the plant normally grows. However, you have shown that it is possible, and that problems will eventually develop. Repotting is one thing that will ultimately be needed as the mineral salts in our water accumulate in the soil and as the plant grows and the roots fill the potting soil. At that time, we may see problems developing. In your case, there are several possibilities:

1. It may be transplant shock from minor root damage during repotting.
2. The new potting soil may have had a high level of salt (some potting soils made from composted manure are high in salt).
3. There may be a foliar disease.

Did you move it to a new place (indoors or outdoors) after repotting? A change in environment can also cause leaf drop. This may be especially pronounced after transplanting.

I suspect transplant shock is the source of the symptoms, but the leaf discoloration also makes me consider the possibility of salt problems or disease. I would watch the plant carefully for a couple of months. During this time, water carefully to keep the soil moist (not soggy), allowing water to drain from the pot. Don't let the drained water be re-absorbed. If the problem persists one or two months after repotting (or if it gets worse before that), take a sample to the Santa Fe County Extension office to have a sample sent to the NMSU Extension Plant Pathologist in Las Cruces. The County Agent, Patrick Torres, may also have some insights to help you.

NOTE TO READERS: Diane wrote back: "Thank you so much for your consultation. The plant is in my office and we recently relocated offices. I repotted the plant in conjunction with the office relocation. Previously the plant faced northwest and now faces southeast. Plus, in my new office, I initially had the plant near the ceiling HVAC vent but read that hibiscus are very fussy about drafts and so moved it as far away as possible from the vent. So, maybe it's just too much change all at once that is the problem. If it doesn't resolve in the next couple of months I'll follow your advice and contact the Santa Fe county extension office. Sincere thanks!"

This strengthens the case for considering a change in environment as the culprit. However, it is important to continue to watch, water so that salt accumulation is minimized, and contact the County Extension office if necessary.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

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