Question
My hydrangea has spent winter in our unheated garage. Do I take it out now, in April, in the area north of Chicago? Also, it’s been in the pot maybe 2-3 years, and I know it needs to be repotted before it gets much new growth. By what point should I repot it?
Answer
Thanks for asking these great questions! You’ll want to keep your potted hydrangea in your unheated garage until after the final spring frost which in your area is around Mother’s Day. I know it’s so tempting when we have occasional sunny days in early spring to bring those hydrangeas back outside, but with your nighttime temperatures still below freezing, you’ll need to wait a bit longer to be safe.
For re-potting, the general rule is that if your shrub seems to be surviving rather than thriving, it’s time to transplant it to a larger size container. You can do this transplanting at any time but it’s certainly easier before the shrub puts on a lot of new growth so I’d take the opportunity to do that now. Measure the mouth – or opening of your existing container and add 4-6 inches: that’s the minimum size your new container opening should be to ensure another few years of beautiful blooms without the need for additional transplanting. Watch this video on planting hydrangeas in containers for helpful tips and reminders about drainage holes, fertilizer, and even some design ideas!