Hydrangeas come just in time to replace fading azalea bloom

Posted: Tuesday, May 29, 2012 8:00 pm

Even with some of those late azaleas we mentioned last week, their season does, alas, finally fade. Summer flowering shrubs to take their place are “far and few between” as the weatherman missaid a few weeks ago.
Relieving the relative dearth are invaluable hydrangeas. The late azaleas overlap some early hydrangeas, while other kinds of hydrangeas take the season into early fall.
Among the earlier hydrangeas are the common bigleaf types with the species name macrophylla (macro: big).
These include the (mostly) blue ones like the old Nikko Blue variety. They are widely seen and have been planted for a century or more anywhere they are hardy.
The bigleafs are root hardy every year, but the top-growth, which does not harden completely some years, is subject to freezing. This is problematic because they do not ordinarily flower on new wood.
Their buds, which are formed the summer before flowering, thus are frozen out of business, and a year’s performance is missed.
The bigleaf hydrangeas are litmus test plants. If soil is acid, and it mostly is in our area, the flowers will be blue. If alkaline soil is evident the flowers will be pink.
A pink florist hydrangea, planted in acid soil, will flower blue the next year, provided it flowers at all.
 With our acid conditions, there seldom are seen any pink hydrangeas, unless the gardener has altered the soil. By adding lime to raise the pH of the soil, pink flowers can be had.
Occasionally, hydrangeas can be seen with pink, blue and purple flowers on the same plant. This indicates a soil pH at about neutral.
The downside of bigleaf hydrangeas is the freezing possibility. Recently there have been introduced repeat-flowering varieties that will bloom on new wood even if the old wood is frozen. The first among them was the popular Endless Summer, and others have come along with repeating lacecap (more below on this kind of bloom) flowers. ‘Twist and Shout’ has been good for me for the past couple of years.
Among the signature plants on our place is a hydrangea named Blue Billow. It has, in 20 years or more, proven to be tough as nails, never having frozen back in all that time. It is a lacecap type, that is, with a row of flat sterile flowers surrounding a mass of fuzzy fertile flowers in the center, thus the “lace cap.”
Some authorities class it as a macrophylla, but most say it is a serrata, or Japanese mountain hydrangea. Whatever, it flowers for a month or more, beginning about May 1, before the blooms turn to a purplish color, then morph into almost red as they dry on the plant.
Blue Billow reaches some five feet tall and as wide. As with most of the early flowering hydrangeas, it is easily divided at the root after a few years. We have many clumps of it, all divided from my original plant received by mail order from Winterthur Gardens when it was unavailable locally.
A parallel plant, though a different species, to Blue Billow is our native Hydrangea arborescens, found in deep woods and edges all over the state.
It is often seen along interstates growing from crevices in stone banks. The flowers are lacecaps, resembling those of Blue Billow, but white.
Our woods had them by the dozens when we moved in 1974, and they still grow there. By moving some from deep shade to more sun, bloom has increased three-fold at least.
This hydrangea will sucker mildly into large patches which, in a wild area, is not a bad thing. The suckers are easily removed if they are not wanted.
“Arborescens” means “tree-like,” but there is nothing tree-like about this plant. It will grow to maybe four feet, with weak, brittle stems.
There are several named varieties of it, including Annabelle, with large globose heads of sterile flowers, and an older one, Hills of Snow, with smaller heads.
Editor’s note: Jimmy Williams is production superintendent at The Paris Post-Intelligencer, where he also writes this column.

Published in The Messenger 5.29.12

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