Plant Diseases/Pittosporum / cream de mint issues
I have several pittosporum shrubs that are showing brown leaves and I was wondering if it is due to watering problems. I water every 2-3 days for 15 minutes using tiny sprayers and when I know a 88-90 degree day is approaching, will water for 20 minutes. ( after a hot day, noticed one or two shrubs with wilted leaves and after watering 20 min, the next day they looked happy again). Do you think I should switch to bubblers or another sprinkler that would water at base of shrub rather than spraying leaves? Am I overwatering? This planter faces south and I live in southern CA. We picked these shrubs due to hardiness and ability to handle a lot of sun. They were planted in late March and have been doing ok until last couple weeks. The four shrubs toward street look much healthier than the ones toward the back...any advice you could provide would be greatly appreciated. Thank you so much for this service!
Dear Dana, Yes, this is due to watering and unfortunately your pittosporum is now "pitiful sporum". Just a little landscape humor there. I think that your sprinkler heads are the ones that blow a fine mist - this type head is really only suitable to mist trays of cuttings or to mist very high humidity tropical plants. You need something that actually puts water on them. Just a general rule: were you to take a hose and run it about medium stream, then you should water each shrub about 30-45 seconds every 3-4 days. What is happening is that the leaves are staying very wet, and the shrubs themselves might not be getting too much water. Stick your finger in the soil just before the watering would start. The soil should be dry down to about the second knuckle. Then check the soil with your finger about an hour after the sprinkler has run. The soil should be evenly moist all the way down. You could just hose water this area in about a minute and a half, but I understand that if you have a lot of plants, a good sprinkler system is pretty important. Now also you may have the shrubs planted a bit in a valley whereas it is generally best if they are planted a bit above the general ground level. Not much, just an inch or so. One more thing that will definitely help you, and also conceal the sprinkler lines and keep them more protected is mulch. I recommend cypress mulch unless you prefer the redwood. Both are very good at creating a mesh and they don't float or attract roaches like pine bark. They are also very helpful at conserving water. If you are concerned about the plants becoming too dry, you could work a little "Crystal Water" into the soil. This substance swells up to 100 times its weight in water, and will keep too much water away from the roots during periods of extra rain, and will release the water to the roots as needed and in drier times. The main thing, however, is to get the focus of the spray off the leaves. I think you will be able to turn the corner on these shrubs in about a month if you change the watering. If you have some that are seem badly damaged, you might want to replace them with new shrubs, or just keep an eye on them in case they need replacing later. I hope this information helps. Be sure to write back if you have further questions. Good luck, Melissa