Question
I have two potted, trellised jasmine vines,6&8 years old, 8 and 12 ft. tall in large pots in a small inner patio covered last year with solar cloth (blocks 85%UV but lets lots of light through). The jasmine and other plants there were getting sunburned last year. Live in high desert area, day temps up to 95, nights in upper 50s during dry season (usually below 30% humidity). I water and mist them every other day. Lately, they've been dropping green leaves which are totally desicated, like they've been freeze-dried! The pots are 12-16"wide, 18" deep with good drainage and water trays below, but not touching the pots. I thought under or overwatering would cause leaves to yellow first, not dry and drop while fully green. Any advice on that?  Also, the larger plant has a lot of white/yellow very small waxy growths on the stalks and leaves, especially near the leaf veins.  They're not fuzzy like mealy bugs, nor give off any sticky substance like scale, nor appear to be a bug of some kind (no movement that I can see under a magnifying glass,anyway) just waxy round dots which are very firmly attached. Doesn't look like pictures of oedema I have viewed. I have tried scraping some off, but that damages the leaf. Also, thinking them some sort of fungus, sprayed copper sulphate over a period of a month.  Problem persists.  Can you identify the problem and offer a suggestion to remedy it?  Thanks.  Jan

Answer
  Dear Jan, I think you have two problems with your jasmine, one is with the watering and one is the small waxy growths.  I will address growths first.  Your jasmine has scale, a common insect infestation of plants.  They do spread easily so you will want to control them.  Scale is an insect which doesn't move in its adult form and lives under a hard protective coating or scale which protects them from most ordinary insecticides.  The best control is to spray the entire plant with horticultural oil (not kitchen oil, it is not the same thing).  This will suffocate the scale and cause it to drop off.  You will know it is dead when the dried scales fall off with no effort or a moderate stream of water aimed at them.  You may have to spray several times about a week apart to get effective control, but this method WILL work. After you spray a few times, you should fix the problem.  Also, just a few tips on watering.  I would probably water less often, but making sure that the plants are watered well.  You may have to judge this because desert climates are always a little different.  The water trays under the plant should be emptied as soon as the plants finish draining off excess water.  The excess water in the tray can cause roots to suffocate and put the plant under more stress.  However, you must be doing a lot right because your jasmines sound gorgeous.  Just spray with the horticultural oil to control the scale and empty the water trays after watering and your jasmine will be gorgeous again in no time.  I hope this information helps.  Let me know if you need more assistance.  Good luck, Melissa