You'll see them in old farmyards, still blooming from August into Autumn. They are PeeGee hydrangeas, with big white blooms in a conical shape. The used to be called 'Snowball Bushes" and for a time went out of fashion. Now they're back, with many different varieties. Hydrangea paniculata is the genus and species.
Technically this is not a tree; it's a bush. To create the tree form growers select a strong upright stem and prune out all the others. They stake this stem and let it branch out at the top, continuing to prune out anything else that grows from the base. After a while they have a small tree that will grow to a maximum of about 20 ft--perfect for a small yard. When you search for a H. Paniculata you must look for the words "tree form"--otherwise you will get a shrub. The tree forms are also more expensive because of the extra work involved.
The name "PeeGee" is from the cultivar name 'Grandiflora' as in "paniculata Grandiflora." In terms of pruning almost all PeeGees bloom on "new wood," which means branches that are new in the Spring of each year. If you prune it back in the winter or early March you are fine--and they can take pretty hard pruning and shaping. If you prune from April on you are cutting off the new shoots where the blooms will be.
If you want a tree form H. paniculata of any size it's best to get one at a nearby nursery. Recommended are Fiore's, The Chalet, and Gethsemane Gardens. The Chalet lists the following in tree form:
'Limelight' --green flowers--8ft high x 6ft wide
'Pink Diamond'--white turning pink--8ft high x 6ft wide
'Tardiva' --white, late bloom--15ft x 10ft
Almost all the paniculata flowers start out pale green, turn to white, then turn to pink over a two-month period. Most of the named cultivars are selections chosen for one factor or another. Fiore has the largest number of cultivars in tree form in our area: 'Quick Fire,' 'Pinky Winky,' Kyushu,' 'Limelight,' 'Tardiva,' 'Unique,' and others. Fiore has #7 containers (about 7 gal.) for $140--often a 5ft+ tree. Gethsemane has an unfortunately incomplete list on their website, which contains no PeeGees. For a nursery with a huge list you can check Wilkerson Mill Gardens in Palmetto, Georgia, which carries Michael Dirr's introductions as well as many others. There is mucho info on their website.
Here is a small tree which could last your lifetime. And isn't it great to see those blooms so late in the summer?
