Hi, I have a large gardenia in a container that I imagine I need to bring it in for the winter? It still has buds waiting to bloom (Oct. 31) but with the cold temperatures, I’m not sure what to do about cutting it back.Do I do that now and leave it outdoors until just before frost? Do I cut back all /some of the branches? When? How much? It’s larger than my indoor space will allow. If I cut back all the branches to 10-12″, will I be sacrificing next year’s blooms? Thank you for your help.
In the fall, gardenias form flower buds for the following summer, on both green and brown wood. The best time to prune the plant is in the summer immediately after the blooms fade, before new buds develop. Your plant either has set its buds for next summer (most likely) or still has a few buds ready to burst into bloom (the latter possibly because of the confusingly warm fall we have had). Note that some gardenia varieties may bloom more than once each year.
The usual first frost date in the GTA is mid-October. We’ve been lucky so far this year, but I’d suggest that you bring the plant indoors very soon. Most gardenia cultivars are not cold-hardy so would not survive GTA winters outdoors. In particular, containers tend to expose plants to freezing/thawing more than would be the case if they were planted directly in the garden.
If the only way you can bring your lovely gardenia indoors is to cut it back to a manageable size, I don’t see any alternative for you. Go ahead and prune it. Try and avoid snipping off flower buds as much as possible. Be prepared for the plant being a bit fussy transitioning to indoor conditions, which are darker and drier than what it is accustomed to in your garden. Expect leaf and bud drop as the plant settles in, and watch for spider mites (insecticidal soap will help control these critters).
You likely will sacrifice some if not all of next summer’s blooms. However, if you keep the plant happy indoors over the winter, then put it outside come late May, it will have lots of time to flourish before setting buds for the following year. If you’re lucky and the plant does bloom next summer, you’ll know exactly when to prune it. If there are no blooms, pay attention to when gardenias are in bloom in your area and prune accordingly, before it sets buds. It is important to prune the gardenia to the size/shape you require to prepare for bringing it indoors again for the winter.
Indoors, keep the plant in a sunny place, ideally near a south-facing window. An alternative is to provide 4-6 hours of light using grow lights. Ensure the spot is free of drafts (not near the air register). Keep the gardenia humid. A mini-humidifier would be ideal. Mist it from time to time, although this does not provide sufficient humidity to keep it healthy. Keep the soil slightly moist (not soggy) – be careful not to over-water.
The gardenia likes temperatures of about 21 degrees C (70 degrees F) during the day and should be kept cool at night, at around 16 degrees C (60 degrees F). The plant won’t tolerate temperatures that fluctuate too much. Note too that if night temperatures are too warm, the plant may not bloom well once it’s put outdoors in the late spring.
All the best in keeping your gardenia happy and healthy!
November 1 2021