This question was submitted by Sara. Researched and answered by Advanced Master Gardener Elaine.
What is your question for a Master Gardener?
I have purchased Lilacs and Hydrangea for my yard in New Palestine. They are in those buckets from Home Depot. I know the best time to plant is Fall or Spring. Should I wait to plant these until September? thanks
It’s good to hear from you again. It sounds like you’ve been busy in your yard.
You are correct that the best time to plan shrubs (or trees) is either Spring or Fall. Fall is usually the preferable time if you are looking to lighten your workload as there is less time until frost to have to water the specimen ( studies have shown root growth to occur down to 40 degrees F.). Otherwise, with Spring planting, you will need to make sure the plant has sufficient water to sustain new root growth the first year. If It is a year with drought, you will be spending a lot of weeks doing that. With Fall planting, the roots should have enough time to establish themselves before the plant goes dormant. The one guiding principle to remember when adding something to your landscape is without a sufficient root system, you have no plant. So when it comes to deciding when to plant something, let that be your guide.
While most sources recommend not planting a woody plant in the middle of summer when temperatures are high, interestingly, I found at least two sources that indicated it can be done for plants grown in containers, which sounds like what you have. You should not attempt planting a bare root or “balled and burlaped” tree or shrub in the middle of the summer. This is because the root systems of both types have been disrupted and planting during the hottest part of the season will add even more stress to the plant. Those trees or shrubs grown in containers have root systems that will not be as disrupted and MAY NOT be as stressed. However, I would use caution if you decide that you want to plant now. I would plant the shrub in the evening as temperatures are cooling down. Water profusely. Do not fertilize at planting as that will add more stress to the plant to produce foliage. Remember, root growth is your focus the first year of a plant’s life. You can fertilize once the specimen has established itself. Do not heavily prune at planting; only remove dead branches, etc. Be sure to check everyday for signs of stress. Water thoroughly when rainfall is absent or insuffient. The shrub will need a minimum of a gallon a week; more when it’s extremely hot. The goal is to make a smooth transition from the pot to the ground and irritate the plant as little as possible.
If you can wait until September to plant, that would be ideal, however, there are situations where it is not practical to leave the specimen in the pot. If something appears to be very root bound, it needs to come out of the pot. You can replant it in a large pot and wait until September but if you have nothing larger to put it in, then you might want to go ahead and plant it.
There are few woody plants that can be planted most anytime, except when the ground is frozen, but Lilacs and Hydrangeas are not one of them. If you do decide to plant them now, just be very attentive to their needs.
Elaine; Hancock County Master Gardener Association