Few plants endure such masochistic pruning as the common Mophead Hydrangea, or H. macrophylla.
The reason being is that we purchase these cute, one-gallon plants of standard varieties such as ‘Nikko Blue’, ‘Kluis Superba’ and ‘Teller Red’ – fully expecting that they will remain a mere two feet tall and wide for the rest of their lives.
Several years and three to four feet later, these same spectacular shrubs that we’ve nurtured and enjoyed each summer suddenly get a starring role in The Texas Chainsaw Massacre, leaving little behind in the way of flowering wood.
What more gardeners should be aware of are the many compact cultivars of Hydrangea macrophylla: ‘Pia’ (pink, matures at two feet high and wide); ‘Adria’ (blue, matures at three feet high and wide); or the CityLine series (available in a wide range of colours), which grows to a mere three feet high and three to four feet wide – so you don’t actually have to hack them into submission.
Your other option is to choose re-blooming or remontant types that, despite a heavy spring pruning, will still flower on new wood later in the season. This way you can control the size without losing all the blooms that you would on Hydrangeas that only flower on last year’s wood.
The original repeat-bloomer Endless Summer (three to five feet high), is still one of the best, with huge, long-lasting true blue rounded blossoms, when grown in acidic soils.
New on the local market this year is the Double Delights ‘Star Gazer’ (three to four feet high), with delicate ringed lacecap blooms of pink florets edged in white, which flower from summer through to fall.
Hydrangea paniculata, or PeeGee-type hydrangeas, are another useful species to grow in gardens prone to hackers. These bear cone-shaped flowers on new wood (from midsummer) and have excellent cold hardiness to Zone 3. It is these last two attributes that makes them such good candidates for growing in large containers, as well as being much more sun tolerant than standard Mophead hydrangeas.
Your compact choices here include ‘Bombshell’ (abundant smaller white blooms, 3’ high), Little Lime (lime green flowers, three to four feet high with pruning) and BOBO (white fading to pink, three feet high).
The midsummer to autumn blooming Oakleaf hydrangea (H. quercifolia, Zone 5) further extends the flowering season and adds textural interest with its oak-shaped leaves and fall foliar colours.
‘Little Honey’ (three to four feet high) is a golden-leaved form that is best grown in just morning sun (or it may scorch), featuring white cone-shaped flowers and reddish-orange autumn tones.
‘PeeWee’ (three to four feet high) bears white cone-shaped blossoms that fade to pink, and more intense autumn colours of burgundy-bronze to a rich maroon-purple.
So now that I’ve given you 10 good reasons (or dwarf cultivar selections) not to hack your hydrangeas, I expect to hear far fewer chainsaws come pruning time.
Mike Lascelle is a local nursery manager and gardening author (hebe_acer@hotmail.com).