Endless (? ?) Summer Hydrangea

As usual, our subzero winters put a big damper on an endless summer of blooms. But with a few careful standard care practices you can increase the blooms.

Endless Summer Hydrangea by Midwest Gardening

Endless Summer Hydrangea bloom on both old wood and new wood. This blooming characteristic can give you an “endless summer” of blooms. Old wood produces blooms in spring, and the new growth produces blooms in later summer. Very late in the season the bud of next springs’ blooms form. Most of the blooms for the season are produced in spring on the old wood. The problem is, in the northern zones 5 and colder the plant typically dies back completely. Hence, there is no old live old wood to produce a glorious display in spring. To make matters worse, the new growth that will produce late summer blooms may not have time to even open before frost hits with our short growing season. Double blow to potential blooming.

I planted an Endless Summer a couple of years ago. The first season it produced glorious blooms all summer and it was interesting that it produced both pink and blue. First, I realize now that coming out of a greenhouse my hydrangea had both old and new growth to produce blooms. Second, I suspect that the pH in the greenhouse soil produced blue blooms, but once in my soil the blooms tended more pink. The second year in my garden it seems to me I had mostly pink blooms but not as many. This is my third year and I had one or two spring blooms and have been anxiously awaiting more all season. With no blooms in late August a gardener friend noted hers had never bloomed after the first year. What? In my whole landscape plan haste had I not researched this beautiful plant enough? We have had two brutal winters since the landscaping went in and record breaking wet spring, but apparently there were things I could have, and can be doing to encourage blooming. Evaluate your site and maintenance practices to see if there is more you can be doing too!

How to encourage Endless Summer Hydrangea blooms

  • Plant in a warm sunny spot In cold climates Endless Summer Hydrangea will need the warmest micro-climate you can find. Give it the longest season possible by planting where the snow melts first in spring. Normally bright morning sun and afternoon shade is preferred, but in the North the afternoon sun is not typically hot enough to wilt a hydrangea, but we have had some pretty extreme heat the last couple of summers. Shade from 2 to 4 or so in the heat of summer would be ideal. At least three hours of direct sunshine is necessary, several hours of morning sun into the early afternoon is best.

  • Prune cautiously Do NOT cut back to the ground, ever! In spring, carefully inspect branches and ONLY cut back those that are clearly dead. I wait until growth begins and let the plant begin to leaf out. The leaves will be produced from the bottom up, so inspect upper branches carefully for bud nodes. Remove upper stems only once you are positive they will not leaf out, no hurry! Northern horticulturalists suggest that cutting the new stems back to half will produce substantially more blooms later. I might try that if mine continues to fail.

  • Patience Sometimes plants just need a couple of years to settle in to a new environment and get established.

  • Feed correctly Endless Summer Hydrangea is a heavy feeder and will need consistent food by applying one spring application of granular slow release fertilizer to bloom well. Over feeding with a high nitrogen fertilizer can damage the plant or encourage foliage growth or both. Use a low nitrogen balanced fertilizer. If you are using a low nitrogen liquid fertilizer begin feeding as soon as growth begins and continue until mid August. The plant will start working on dormancy at that time and growth should not be encouraged during that period.

  • Consistent, even watering Your Endless Summer should be planted in well drained soil. The soil should not be allowed to dry out or become saturated. Over watering will inhibit blooming and stress from parched soil will also cause fewer blooms.

  • Deadhead Remove spent blooms to encourage more production.

  • Winter protect Oh boy, not another one to protect in winter? We might have to resort to that if everything else we do doesn’t help. Like marginally hardy roses, you can cage Endless Summer in chicken wire and fill it with dry fall leaves. Covering the top, ONLY the top, with plastic will help to keep it from getting compacted with heavy wet snow. Wait until the plant is fully dormant after the ground freezes.

  • About the color Like the Nikko Blue Hydrangea, you can manipulate the color of Endless Summer blooms. I personally do not suggest doing so, as it is a never ending battle with the pH levels. Your soil has a natural pH this is nearly impossible to alter long term. Let Endless Summer do it’s own thing, I will be grateful to just get blooms!

No single thing should normally cause Endless Summer to fail to bloom. But of course in cold climates the plant will already struggle to bloom well, so every best maintenance practice you can manage will help.

Sharon DwyerComment