OK, lets do a little math. Let's say you have a one gallon emitter on each plant. You're watering 90 minutes, 3 times a day. That's 4.5 gallons each time you apply water (assuming you don't have clogged emitters). A three foot shrub needs about 8 gallons of water each time its' applied. Visualize that one gallon of water will moisten one cubic foot of soil. 8 gallons would moisten an area 2' x 2' by 2 feet deep. That's just about right for your plants now but as they grow they'll need more water. Watering deeply pushes any accululated salts below the root zone which can cause yellowing leaves. A better strategy for watering is to apply the water once a day rather than 3 times a day. Allowing the soil to dry a bit helps oxygen return to the soil - roots need oxygen in order to absorb nutrients from the soil. Every three days this time of year is probably OK for your hibiscus. Desert adapted plants can get by with once a week watering. Instead of rock mulch, have you considered using a 3 inch layer of organic mulch? It does several things. 1) slows evaporation; 2) keeps soil cooler; 3) releases nutrients back into the soil; 4) reduces reflected heat and light on the plant. Hibiscus are acid-loving plants and they struggle here in our salty soils. Once a week or so use a teaspoon of white vinegar in a gallon of water and apply it to your hibiscus. This will help neutralize the soil a bit and make your plants happy. Good luck.

I also have a problem with a hibiscus tree I just bought from Lowe's. It looked great for a week or two, and then we had a really big rain and the leaves started wilting, and before I knew it, they all fell off and there is nothing left to the tree. I realized the pot that the tree is planted in did not have any drain holes, so we immediately drilled holes in the bottom of the pot, and replaced the soil in case it was mildewed. It has been about 2 weeks since then, and the treee is still not coming back, even though it has gotten plenty of water and sun. I don't think it's completely dead because when I scratch beneath the surface, I see green. I don't know what else to do.

Hello everyone. I usually hang out on the hosta forum, because I'm a hostaholic...lol! But, I have a hardy hibiscus that is on it's third year in my sun garden. It looked wonderful, increasing by leaps and bounds. Not blooming yet, but getting ready to. Anyway, today I noticed that 4-5 stems have turned dark brown/black about 5-6 inches up from the soil line. One of the stems is actually falling over at the soil line. The leaves still look good, no wilt so far. What could be the problem and is it going to spread? Could too much rain cause it? We've had lots of rain this spring/summer. Torrential downpours. It is in a well drained area and doesn't appear to be have any standing water. But, I'm sure it's been getting plenty. My hostas like it though!....lol Can anyone help me? Thanks.

First off, it is infested with mealie bugs. Those white spots that are fuzzy are the mealies. I would go and get an insecticide soap and /very/ thoroughly spray it all down, inside of the curled leaves, the backs of the leaves, the stems. Any white mealies should be rubbed off (they don't bite). Wait about a week and then spray it down again a second time. Don't let it get full sun again until it's dry so the spray doesn't make the leaves burn. Mealie bugs aren't difficult to get rid of and don't require very potent chemicals to do so, merely your being thorough about it. That may be the only issue. But once you get rid of the bugs you can see if the leaves begin to unfurl, and especially if new leaves begin to be made open and flat. Other things can also cause curled leaves including mites or deficiencies so make sure you are feeding using a well balanced fertilizer with trace minerals. If you cover both of those and the leaves stay curled, just pray it's not leaf curl virus on top of everything else. The good news is it's probably not virus.