10 Neat Things about Hydrangeas
1. Five
There are about 75 species of hydrangea in the world, but only five species typically grown in Canada. Two of them are hardy to zone 3: panicle (Hydrangea paniculata) and smooth, or Annabelle (H. arborescens). The other three are hardy to zone 5: bigleaf (H. macrophylla), oakleaf (H. quercifolia) and mountain (H. serrata).
2. Climbers.
There is a sixth not included above: the climbing hydrangea (H. petiolaris). It takes a while to get going, then there is no stopping it. It’s like a sleepy thug. It is very hardy, though, down to zone 2, and likes part sun to full shade.
3. Colour changers.
If you want to change your hydrangeas from pink to blue (or from blue to pink, which is more difficult), you need to start with bigleaf or mountain hydrangeas. None of the other hydrangeas change colour based on the pH of the soil. If you have acidic soil, your bigleaf and mountain hydrangeas will be blue, if your soil is alkaline, they will be pink. If your soil is near neutral, the flowers will probably be purple. Changing the pH of your soil is a long-term endeavor; you can learn more about it here.
4. Why “hydrangea”?
The first part of the word, hydra, means water. If you have hydrangeas, you will know that they like water a lot. The name may refer to that, or, more likely, to the seed capsules, which resemble water vessels used in ancient Greece.
5. Drought tolerance.
If you’re looking for hydrangeas that will accept a little less watering, go for panicle and oakleaf. They are reputed to withstand drought a bit better.
6. Plant them well.
Hydrangeas can be long-lived, reaching 50 years or more. Make sure you give them enough water, but don’t let them stand in water—they won’t tolerate that. Plant them in well-draining, rich soil, and mulch to keep the moisture in.
7. Pruning.
Panicle and smooth hydrangeas bloom on new wood, so you can prune them any time before they leaf out or after they bloom and they will reward you with a beautiful display of flowers. The other types, including climbing hydrangeas, bloom on old wood. If you prune them at any time, you may be pruning flower buds. It is best not to prune them or to accept that they will be less floriferous for a year.
8. Where are they from?
Hydrangeas are from East Asia and… surprise!… North
America. The native hydrangeas are oakleaf and smooth.
9. ‘Annabelle’.
If you are a native plant fiend, you may have an inkling that this means you should generally be looking for the species form of plants; you should be looking for, say, the columbine Aquilegia canadensis rather than Aquilegia canadensis ‘Little Lanterns’. H. arborescens ‘Annabelle’ is a little different, though. This variety was found as is, near Anna, Illinois, in 1910. It is a cultivar that cultivated itself!
10. 'Incrediball’ and ‘Invincibelle’.
The problem with ‘Annabelle’ is that the big flowerheads often overpower the stems, causing them to flop. ‘Incrediball’ is a smooth hydrangea that has been bred with stronger stems. ‘Invicibelle Ruby’ is another smooth hydrangea that has a blush of red!
