In Your Garden: Hydrangeas

People are always looking for bushes that will bloom from spring until fall but unfortunately there aren't many that will do that in Illinois.  We have to do a bit more planning to enjoy blooms all season and for summer, Hydrangea fit the bill.

There are four main kinds of shrub hydrangea that tolerate a range of conditions making them a great fit for almost anyone's garden.  Some like more sun; some prefer shade, some more dry and others more damp soil.  The one thing they all share is a strong resistance to insects and disease meaning they're a fantastic low maintenance shrub.

Smooth Hydrangea is a native to North America that you can buy as a native or hybridized cultivar.  The most common cultivar of this is the Annabelle Hydrangea known for its' white mop head blooms that often reach 10 inches in diameter.  In our area, Annabelle hydrangea can tolerate full sun, though it needs plenty of water to get established.  Ideally, morning sun and dappled afternoon shade provide the best growing conditions.  The flowers can be hung upside down to dry and will last a long time in dried arrangements.  Smooth hydrangea should be deadheaded in the late fall and can be cut completely to the ground and will bloom again the next year.  New cultivars of smooth hydrangea bloom pink rather than while.  Look for varieties named Bella Anna or Invincibell Spirit.

The Oakleaf Hydrangea is my favorite in the hydrangea family.  Another North American native plant, this sturdy and beautiful shrub offers four seasons of interest.  Early spring foliage emerges dark green and coarse followed by summer blooms, usually in June.  The blooms are white and cone shaped appearing at the end of nearly every stem.  The larger the plant, the more blooms you'll have.  The white slowly fades over the summer turning rusty red and eventually brown in the fall.  Fall color on Oak Leaf is outstanding turning shades of orange and deep red.  In the winter, the peeling cinnamon colored bark really stands out against the snow.  Plant Oakleaf hydrangea in the sun or the shade and make sure they have a well drained soil.  Oakleaf can handle very dry soils once it's established, but will not tolerate wet feet for long.

Hydrangea paniculata, or PeeGee hydrangeas are the largest and probably most versatile hydrangeas.  They produce large cone shaped blooms that usually change color into pinks and reds as the blooms age.  PeeGee are also the only hydrangea that grows large enough to be pruned into a tree form.  This hydrangea can be pruned any time except when the bloom is forming making it easy to keep tidy. There are many cultivars of PeeGee on the market that offer different bloom colors and plant sizes making this a versatile plant for all areas.  Plant PeeGee in full sun or dappled shade as it will not bloom or develop pretty fall color in heavy shade.  Keep it moist through it's first year and mulch it well and PeeGee will reward you with a beautiful show.

The final hydrangea in the shrub group is the Big Leaf Hydrangea or Hydrangea macrophylla.  In the last decade, this type of hydrangea has gotten a lot of attention.  Most big leaf hydrangea bloom on growth from last year, but in Illinois our winters are too harsh and we don't have enough snow so the plants would often never bloom.  Newer introductions of big leaf hydrangea actually bloom on new growth meaning they do not have to survive the winter to bloom.  Morning sun and afternoon shade or dappled sun all day long is best for these plants.  If you plan on planting more than one, I strongly suggest you add a soaker hose under a four inch layer of mulch to keep the roots cool.

 Hot and dry conditions in July and August make these plants the first to wilt.  Typically when you buy these, the blooms are a vivid blue though white and blush flowers are available too.  If you want to keep them bright blue, you'll need to acidify the soil with Aluminum Sulphate or Ammonium Sulphate when you plant and add more each year.  If you choose not to acidify, the plants will bloom pink. In my experience, the plants take two to three years to establish before reliably blooming in the landscape.  Don't give up on them if they don't bloom the next year.  It takes patience for these to settle in.   Big Leaf Hydrangea is the most challenging of the family to grow, but the color, bloom size and number of blooms make it a challenge worth accepting.

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