I live in Wisconsin and have a potted Star Jasmine (18" pot, the plant itself is approximately 36" tall) which I over-winter in the house in a south facing window. Since purchasing it 2 1/2 years ago, each winter it loses nearly all of its leaves, even though there is regular new growth (which also falls off). In the summer it becomes lush and amazing and blooms like crazy! Last spring/summer when I moved it back outdoors I noticed it had spidermites, so I treated it with systemic granules and religiously sprayed it every day or more with a mixture of dish soap, rubbing alcohol, and water, and erradicated them. It became absolutely healthy and gorgeous! This fall when I brought it indoors, I noticed it had spidermites again, so I treated it with the same methods I had used in spring (unfortunately it also infested a number of my houseplants!). I haven't seen any webs on the leaves or branches for awhile, so I think the mites are gone, but it continues to drop leaves like crazy and yet produce new growth. Predominantly the dropped leaves are green, but a few have been yellow or dried up and brown. I water it very thoroughly once every 1 - 2 weeks and have given it fertilizer once thus far over the winter. What the heck is going on? Is this what Star Jasmine's do over winter when they're forced to live indoors, or do I have some other problem that I haven't identified or the mites are still the problem? The few mature leaves on the plant look shiny and deep green, but then they fall off! Help!
Trachelospermum jasminoides , Star Jasmine, goes dormant in the winter. This is true also for plants that are container grown and overwintered indoors. During the winter, they need minimal water and no fertilizer. In order to keep the plants green, they need at least 4 hours of good bright sunshine from a South or West window during winter
. I would imagine that most of your leaf drop is due to overwatering and fertilizing while the plant is indoors and in a dormant state. As a rule, no fertilizer and watering lightly (just enough to make the soil moist, not wet) once a month should be enough. It is also stressful to the plant if it is in hot or cold drafts. It is normal for a few leaves to fall when the growing conditions change...bringing it indoors will cause that to happen.
Thank you for your reply, themoonhowl. I do let it dry out between waterings and I think my quantity qualifies for moist as opposed to wet - I prefer to "neglect" watering my plants rather than watering them too often. My big concern is how bare it has gotten these past two winters. It doesn't drop just a few leaves - it drops nearly all of them! Drafts aren't an issue in this case. Thanks for the tip about fertilizing. I won't give it any more until spring.
You are welcome. I really think it is just reacting to the reduced light. Some of the sites I looked at say to stick it in an area where the temp stays around 50 degrees for the winter with no added light and water once per month...then when moved outside in spring the plant will break dormancy and start growing again and should be fertilized at that time.