In the depths of winter, when the air is cold and dry outside and hot and dry indoors, there is no indoor plant we cherish more than Jasmine polyanthum. This beloved subtropical vine forms a trailing mound of small leaves and curling tendrils. The dark green glossy foliage is beautiful to look at, but it’s the small white flowers and the heavenly fragrance they release that makes this plant such a treasure. The perfume can fill a room, and no matter what the weather outside, it lifts our spirits by conjuring warmer, balmier places.
Our Jasmine plants are grown here in our greenhouses, which are overseen by Nursery Manager Barb Pierson and her staff. They’re shipped to customers starting around mid November and can be shipped through late March, depending on the weather. We asked Barb to talk about Jasmine and to offer a few tips on how to keep these plants thriving through their season of bloom or beyond.
“There are lots of varieties of jasmine,” Barb says. “Confederate Jasmine is the one you see growing down south. It’s not for indoors. Ours is Jasmine polyanthum. You don’t often see it in the landscape. It’s more of a houseplant. Other indoor varieties don’t produce the same number of blossoms. Jasmine polyanthum gives one big flush, which may continue for weeks. The fragrance is in so many perfumes, soaps, candles and infusers. In addition to the fragrance, the vine itself is lovely, delicate yet strong, the dark green leaves spaced along tendrils. The small, star-shaped white flowers stand out against this lush, beautiful background.”
Last summer was “super hot,” as Barb puts it, and while Jasmine polyanthum doesn’t like that kind of heat, the plants did beautifully, largely thanks to Sam, the staff member who tends them. “She’s now a seasoned jasmine grower,” Barb says. “She’s been doing it for at least four years, and she doesn’t let them get too dry.”
The key to keeping Jasmine polyanthum happy is to give it “steady, even moisture,” Barb says. “If jasmine gets very dry, it doesn’t bounce back. At any point in their life cycle, if you let the plants dry down to where they’re physically wilting, they really don’t bounce back without getting brown leaves and looking awful. These plants like humidity – you can spritz them or use a humiditray.”
While some customers keep their jasmine plants and summer them over to encourage rebloom the following winter, the majority (and most of our staff members) treat the plants as winter “annuals,” tossing them out when the bloom cycle is done. If you do choose to keep a Jasmine polyanthum plant going through the warmer months, take it outside in spring once temperatures have settled above freezing, and give it a shady spot. The plant will appreciate fertilizer. “They take a lot of feed,” Barb says. “We use Organic Gem® Liquid Fish Fertilizer, a foliar feed, and they really like that. (Be advised that the smell persists for two days so do the feeding in summer when the plants are outside.) Feed them once per month from April to the end of October. Use a water soluble fertilizer for houseplants, and use it at half the recommended rate.”
In autumn, the plants are cooled naturally. In mid-September, “we begin cooling them to 42 degrees F at night,” Barb says. “This is part of what initiates flower formation. Starting in mid-September, we hope for cool nights, not below 40 degrees F, until mid-October. Then we turn up the heat gradually to 65 degrees F.” The days begin to shorten at that time of year. “That’s probably a trigger, too,” Barb says, “but we have no scientific material to back that up. Indoors, the plants don’t like hot air from radiators or fans blown on them. They prefer shade to bright, indirect sun. They do not like direct sun.
If you summer over your plant, “Stop pruning by August 1 or you will lose blooms,” Barb says.
“We start shipping jasmine around Thanksgiving when they’re fully budded and ready to begin flowering. We’re sometimes delayed if the fall is warmer than usual,” Barb says. “They can take the upper 20s in temperature so shipping continues, but we try not to ship after it’s below freezing.” If the box is left on someone’s front stoop for hours, the buds will fall off.
“They like 40 degree to 50 degree cool weather, and the flowers last longer in cooler temperatures. A cooler room of the house with bright indirect light is ideal.”