Problem with Artemisia Powis Castle

Hi,

I live in San Diego and changed my yard to a xeriscape garden instead of grass. In addition to other plants, I planted three 1 gal. size artemisia powis castle in a 1/2 native soil, 1/2 enriched soil mix in full sun, watering 1 gallon every 4 days. The artemisia have grown to about 2 feet in diameter and were doing well until about April. Then about all the interior stems and leaves up to about 1 foot in diameter from the center turned black, the leaves falling off. This happended on all three plants. The outer stems and leaves are still OK. Does anyone know what is going on and if there is a way to treat this condition?

Thanks,
Rich

Is that a sprinkler head? Do you water with a can, a hose, or with an irrigation system?

Looks like too much water.

I agree, leaves turning black and falling off definitely sounds like too much water. If you're watering it via the sprinkler system it could be since it's sitting smack on top of the sprinkler head that it's getting more water than the other plants in the area. Or I don't know how the grading/drainage is in your yard, but I've seen in some people's yards there's a little dip right around the sprinkler head and water tends to collect there and sit for a bit longer than anywhere else, and since that's so close to where your plant's roots are that could be the problem.

Thanks everyone for your comments. I don't think it's an over-watering or leak problem. The plants are on a drip system, they each get 1 gallon over the course of an hour (xeriscape system), once every 4 days. The item in the picture is a manifold for the drip system, which has 1/4 inch lines going to 1 gallon per hour drip emitters at each plant in the yard. This is a very small amount of water compared to a spray sprinkler system, which applies water in gallons per minute. There are no leaks near the manifold. The other two plants are nowhere near a manifold and have the same problem.

I still think it's too much water--I can't think of anything else that would cause the leaves to turn black and fall off like that. I don't think you need that much water every 4 days if it's a xeriscape garden, most of my garden even in our worst heat wave I don't water more often than once a week, and less than that if it's not that hot out. I'm not using my drips this year because I'm not sure they're the best thing for xeriscape plants and California natives (which is what a lot of my garden is) but last year I was running them 20 min every 5 days (1/2 gph drippers). I had a couple Artemisia 'Silver Mound' in one of my beds and they did just fine. (this year if I were running the drips, I'd run them even less frequently since the plants are better established, but last year was their first full year in the ground). I'd go out just before the next time your plants are going to be watered and stick your finger down a few inches into the soil and see how it feels, that'll tell you whether you're watering too much or not.

I agree that perhaps your artemisias are getting alittle too much water. I grow the Powis Castle here too and though I've never had that particular problem, mine are in a pretty dry spot. The other thing I wondered about is your mention of soil composition. What is your native soil like and what is the soil mix you added enriched with? Perhaps the soil is actually part of the problem if it is holding too much water or is too rich a mixture. I think artemisias are not particularly fond of anything special in the way of plant treats.

Kathy

Thanks everyone for your input. I'll try cutting back on the water, although it may be too late for the Artemisia. I may have to replace them if they don't come back.