Q.
Is it too early to fertilize now my oleanders, lantana, rosemary, and chase
tree?
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| This could be temperature, nitrogen or iron. Try different fertilizers. If you find the right fertilizer it will become darker and greener. That’s how you know its a fertilizer problem. |
A.
You can fertilize now (October) and skip the spring application. Woody plants put
nitrogen fertilizer (whatever is “left over”) into “storage” until spring. The
only plants you want to skip are the so-called “winter tender” plants which you
don’t list (except the tops of lantana which are damaged at 32F). Those are the plants which are sensitive to winter cold damage and include most of our citrus and freeze tender plants like bougainvillea. You
don’t want to stimulate new growth that could be damaged by freezing temperatures. This might include the more tender dwarf salmon colored flowered oleanders (5 foot and tender at 20F) but not the traditionally big ones like the reds and white flowered types (18 foot) which are cold hardy to about 10F.
Skip fall soil applications of iron
fertilizers and wait to correct yellowing due to iron in early spring. Plants will respond to
soil applied iron fertilizers best in the early spring. Fall applications of iron fertilizers are
best when sprayed on the leaves. Use liquid detergent like dishwashing soap or (best) use a spray surfactant such as a wetting agent when you spray. Also it is best to use distilled water so the pH is not alkaline or acid. Better for iron uptake by the plant through its leaves. Makes more iron available.