Plant of the week: Hydrangea

April 8, 2014

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Oh, where to start!  There are so many Hydrangeas available that I can’t possible cover them all, but I will do my best to cover those that are readily available here and that perform well!

Let’s start with one of the most common and reliable in Southeast Michigan.  This is Hydrangea arborescens, and the most common cultivar is ‘Annabelle’.  Annabelle blooms reliably in spring and summer, grows about 3-5’ and makes a great mass planting.  The downside of Annabelle is that the blooms can sometimes be so heavy that they can bend the stems to the ground.  Plants can be staked to prevent this and with any Hydrangea, do not allow them to get too dry.  Some other new introductions of Hydrangea arborescens are now available, including ‘Invincible Spirit’, which is a pink version, as well as ‘White Dome’ which has sterile flowers and strong stems.  This species does best in partial shade to full sun with adequate moisture.

Another popular species are Hydrangea macrophylla.  These are the ones typically used as florist hydrangeas.  Here in southeast Michigan these often do not flower due to mismanagement or late frosts.  These Hydrangeas typically bloom on old wood, which means they set the buds the year before they bloom.  This leads to problems when people cut their plants back too late in the season and the plant doesn’t have time to set new buds.  The other reason your Hydrangea may not bloom is if we have a warm up in the spring followed by a late frost which then kills the buds, resulting in no flowers.

Recently there has been a boom in Hydrangea breeding which has resulted in several cultivars that set buds on new wood.  This is great for our area because you may still see some blooms even with a late frost, although the best display occurs when the buds on the old wood are not damaged.

Some of these new cultivars are ‘Blushing Bride’, ‘Endless Summer’ and ‘Twist and Shout’.  ‘Twist and Shout’ is unique in that is has lace cap blooms.  The macrophylla Hydrangeas do best in shade to part shade, in a moist well-drained soil.

Hydrangea paniculata cultivars do very well here in the Ann Arbor area, and several new cultivars are rebloomers that last a very long time in the landscape.  A few of my favorite cultivars are ‘Limelight’, ‘Vanilla Strawberry’ and ‘Quickfire’.  Panicle Hydrangea can be planted in part sun to full sun and is more drought tolerant than the previously mentioned species.

Oak leaf Hydrangea, or Hydrangea quercifolia is a hardy Hydrangea that does very well here in Michigan and has the added benefit of having one of the most beautiful fall colors available.  The white blooms occur in the late spring and summer.  This plant has a very course texture and contrast well with other plants.  The species is quite large, growing 6-10’ tall, although there are several cultivars available that are more dwarf.  Oak leaf hydrangea does well in partial shade to full sun, and will tolerate drought and occasionally wet soil.

Finally, we have a very unique form of Hydrangea that grows as a vine.  This is Hydrangea petiolaris, and it blooms white blooms in the spring and summer.  This vine grows on structures by sending out small aerial roots that will grow into tree bark, wood, brick or soil.  The vine also displays a yellow fall color, and has very nice dark green foliage during the rest of the season.  This plant does very well in partial shade and well drained soil.

Well, this just barely scratches the surface of all the Hydrangeas out there, but between all of these you are bound to find one that works well in your landscape!