Yucca Damage May Be Preventable With TLC



Damaged Yucca

Q. Any thoughts on what is going on with these plants? I think it is over watering and would like to know how much water and how often it should be watered in the summer and winter. They are on drip. Thanks.

A. The problem is that overwatering and underwatering and some other problems can have the same physical appearance. I would tend to agree with you that it is a watering problem most likely or a drainage problem where the water cannot freely drain from the roots.  I do not think it is an insect or disease pest problem.

These look like maybe either Spanish dagger, Spanish bayonette or recurved yucca. It is hard to tell from the picture. The leaves are heavily damaged with dieback and discoloration. I will post it on my blogspot because I have had others send to me similar pictures.

Yuccas can have some variability on where it is best suited for planting depending on the species. In some yucca they must be watered more often or put into less stressful locations than others. Some are more cold hardy than others. It is a bit hard to generalize unless we know which yucca it might be.

Closeup of Damaged Yucca

Bottom line, these should be watered deeply, not with trickles of water from an emitter. So about ten to 15 gallons each time you water. Then, depending on the species it might be as often as once a week in midsummer.

This is possible it might be a location problem depending on the yucca. If this is a hot spot in the yard with lots of reflected heat and light this might be a microclimate problem. Some of the yuccas are native to the Southeastern US and may be a bit sensitive to our soils and climate or microclimate if not protected. Don’t assume they are necessarily all desert plants and can be treated like many cacti native to the desert. They aren't.

I don’t like it that it appears to be growing in rock mulch. It might be all right but its tolerance to heat and dryness will be affected by the soil conditions as well. They are always a bit better off and more tolerant to stress if the soil is at least somewhat enriched. Even cacti like an improved soil and perform better!