Star Jasmine Needs Sun and Watered Like a Shrub

Q. I am hoping you can tell me what is wrong with my "star jasmine". These plants are approximately twenty years old. The wall they are growing on is north facing. I have pulled the rock mulch away from the base. I mix in compost to each plant every spring when I fertilize. Could it be the irrigation is too close to the trunk?

Star jasmine is from the area of Japan. The great deserts of Japan...not!!! It is not a xeric plant and so it can get yellow, iron chlorosis, in rock. Plant it with compost in the soil and build up the organic content.

A. Without looking at the pictures I was expecting them to be yellow. That’s usually what happens to star jasmine in rock landscapes. Your addition of compost to the soil is keeping them green and healthy.

Bare wooden stems can sometimes happen when it is in poor health or covered with shady growth on top.

Perhaps Watering too Often

Bare stems on older growth can be a natural occurrence. I don’t think it is in your case. It is possible if the water applied is too close to the stems AND it is being applied too often then you can end up with bare stems. It is best if the water is applied at 12 to 18 inches from the trunk (stems, base) of the vine.

Water, when it hits the soil, spreads out. In soils that are very sandy then this distance might be 12 inches from where it is applied. If the soil has a small amount of clay in it then the spread is about 18 inches from where it is applied. In soil with lots of clay (most of the soils in Las Vegas do not have that much clay) then water can spread out from where it was applied from 4 to 6 feet. A happy medium is 12 to 18 inches from the stems or trunk.

Be careful of applying water too often. It can keep the soil wet too long. This can result in leaf drop followed by bare stems. It is always best on plants that have deeper roots (like your jasmine vine) to apply water less often. Vines like star jasmine are deeper-rooted, like medium sized shrubs. Water should wet the soil 12 to 18 inches deep each time is applied. Water your vines like they are medium sized shrubs.

What to Do?

What can you do with bare stems? Cut them back no closer than three or four inches and they will send out “suckers” and those suckers will fill in open spaces if the vine is alive. You may have to cut alot of stems back and start over if it is bad.