My pretty hibiscus plants are covered or almost covered with a white sticky, flimsy netting-like substance. A few years ago, we were told it is White Flies and to use Neem Oil. My son tried Neem Oil, but it didn't help that much. But I think we didn't do it correctly or not enough. Is there an excellent homemade remedy we can use?
White Flies do not produce a white sticky, flimsy netting-like substance.
Also, they're found on the under of the host plants' leaves and cause the leaves to turn yellow. When distributed, White Flies fly off in mass and get their name from its color. So the original diagnosis was incorrect. Neem Oil is a recommended control for White Flies.
Powdery Mildew or Spider Mites are the primary suspects. Powdery Mildew is an airborne disease that coats the foliage with a white film. Spider Mite produces a white netting usually found on the undersides of the leaves. So from your description, I'm going with Powdery Mildew as your problem.
Powdery Mildew attacks a wide range of plants, especially those in the afternoon shade with poor air circulation. Moist air from the marine influence is also a cause as the leaves to stay moist after the sun goes down.
It's continuously a summertime problem. There are several organic controls for Mildew. They include Baking Soda, Horticultural Oil, Baking Soda and Oil, and Neem Oil. Again, these are only controls as there are no eradicants.
You'll need to make frequent applications to keep the Mildew under control. Unfortunately, the final solution may be to replace the plant with those that will cope with this location.
Can I divide a ten-year-old Rhubarb plant?
Absolutely, dividing Rhubarb is the primary method of propagating it.
Rhubarb should be divided every four to six years or when the stalks begin to thin out. It's recommended to divide the clumps in the late fall or early spring.
You first cut the foliage off at the ground, weeks beforehand. With a shovel or a garden fork, the clump(s) is dug up, and you wash off the dirt, exposing the root tubers and crown. With a sharp knife, you segment the root tuber, including a portion of the plant's crown.
Select the largest tubers with three to four eyes for transplanting and discard the rest. The eyes are the pink buds located at the top of the roots. It's not necessary to transplant them right away.
Bareroot Rhubarb clumps are planted in February through early March. Those dug up in the fall can be stored in a dry location until your ready to plant. The new plants should be spaced every three to four feet, and the holes should be generously amended with soil amendments or compost. Rhubarb is a heavy feeder, so feed frequently, March through September, with an organic fertilizer for shade-loving plants. The edible portion is the vegetative stalk. You would harvest the new Rhubarb in the second season after planting.