I know you're not the expert on shrubs, but there is no expert for shrubs on this website, and the two tree experts are on vacation. I thought you might be able to give me some advice on oakleaf hydrangeas in Kansas, since you used to or currently live here. Do oakleaf hydrangeas, particularly 'Snow Queen' and 'Ruby Slippers' grow and flower well in Kansas? I was most concerned about the cold weather and a late freeze nipping the flowering buds. Would there be any chance of that happening here in my zone 6b? Please tell me what you know about growing oakleaf hydrangeas in Kansas.
ANSWER: Hi Tim,
Thanx for your question. A friend of mine just moved back to Kansas City recently and I would go out to visit her in Manhattan. She had some beautiful oakleafs in her front yard and they bloomed and were quite lush.
I have seen the oak leaf do quite well here in the Kansas City area on both sides of the state line. We are in/or on the edge of Zone 6a. I think for areas in Central and Western Kansas which are much drier than the Eastern 1/3 of Kansas, you'll want to ensure that you appropiately hydrate your oakleaf once a week with a good soaking during the hot, dry months of July and August. Additionally, soil is much more alkaline and you may want to amend with smoe well-composted manure in the spring and mid-summer to make sure there are plenty of organic materials in the soil around the plant. I would also plant the shrub in an area that is not exposed to direct sun for more than 6 or 8 hours. The ones I've seen in the Kansas City are were all planted on the north side of buildings/houses or were given shade in the afternoon by surround ing trees. The shrub in Manhattan was planted in a north-facing direction and sheltered by tall trees growing up and down the street. I think the key is plenty of hydration, soil amendment and shade in the afternoon.
I hope this helps.
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QUESTION: Thanks, Tom. You are always very helpful, and that is very good advice and exactly what I was hoping to hear. I will be planting my oakleaf hydrangeas on the north side of my house. They will be replacing my hostas, which do fine in the spring and early summer but tend to scorch and burn in mid to late summer.
Also, I have heard that a late freeze can nip the flowering buds on hydrangeas. The only thing that I was curious about was when the flower buds become vulnerable to a freeze. I know that oakleaf hydrangea produce flowers on old wood, so the flower buds begin to set on the branches around August – September. Obviously those buds aren’t vulnerable to a freeze yet, otherwise they wouldn’t make it through the winter. So exactly when would I need to cover up the oakleaf hydrangea plants to protect them from a late freeze? Would the flower buds be vulnerable to a late freeze March, April, or May? Please let me know what you can tell me about this?
Sorry I took so long to get back to you. I must have missed a notification from Allexperts. The oakleaf is the only hydrangea native to the US as far as I know. It's a pretty tough customer and frankly, I'm surprised I don't see more of them here in the Kansas City area. I've never seen anyone cover them and they seem to bloom quite nicely every year. The less hardy hydrangeas seem to be susceptible to the late freezes in April. So, I'd keep a close eye on the weather forecasts from say March 20 to late April and then throw a sheet over the shrub as needed. Don't use plastic or something else that doesn't breathe. An old cotton sheet seems to be the best way to go. I hope this helps.