I don’t pretend to understand the environmental factors that determine when flower buds are formed on plants, or how quickly reblooming plants reset flower buds. It seems that temperature is the primary influence for many plants to set flower buds, but other plants are more effected by hours of daylight.

I’m quite certain that I’ve heard someone (or lots of someones) declare for the past fifty years that whatever year we’re in has had the most unusual weather ever. Of course, there’s always something peculiar about that year’s weather, but by year’s end most are very average. Except this year! In this statistically warmest year ever, far above average winter and early spring temperatures have caused many plants to flower weeks ahead of schedule, and for plants that rebloom this has added complications.

In last year’s unusually mild late autumn Encore azaleas flowered through November, and ‘Autumn Amethyst’ had a few blooms remaining in early December in my northwestern Virginia garden. Still, the Encores set new buds to flower in late March, a month earlier than normal. In the deep south Encore azaleas flower early enough that they often reset buds to bloom again in mid summer, and then again in the autumn, but in more northern areas they flower in the spring and again in late summer extending into early autumn.

In early August the flowers on ‘Autumn Twist’ are struggling with the extreme heat. ‘Twist’ is the most dependable and longest lasting autumn bloomer in my garden, but the flowers melt quickly in one hundred degree heat. Occasionally, I’ve had flowers on a few Encores late in the month, but these are several weeks early. Fortunately, other Encores are not flowering yet, so there will still be a good floral display in September and October. Is ‘Twist’ flowering early enough to reset buds by late autumn? Perhaps if November and December are as warm as the months were last year, but I wouldn’t bet on it.

The reblooming hydrangeas typically flower late in the spring, and often have sporadic blooms through the summer. With the extreme heat this year they have been slow to reset buds for the late summer bloom, so I expect this will be a bit later this year than is usual. I’m quite certain that the lack of bud set is a result of the hot temperatures. In a few mild summers the hydrangeas have reset buds to flower through July and August, but this year blooms have been scarce in the summer months.

In the past week temperatures have turned a bit more moderate and rainfall has picked up, so I expect the hydrangeas to get going setting buds that will flower late in September, only a little tardy. With less severe heat the Encore azaleas with fat buds but no flowers are likely to pop into bloom very soon.

2 Comments Add yours

  1. BillP says:

    My four Encore’s are right on track with yours here in Millersville, MD, just north of Annapolis. Deferred to your earlier comment that fertilization wasn’t really needed for established plants, and Voila! all of them are simply robust and flourishing with buds ready to bllom. It may be October at this rate, but no matter. One curious thing is happening with a gifted dwarf Azalea adjacent to my Encore’s. It’s getting reeady to bloom as well for the first time this year!?!

    1. Dave says:

      I don’t recall the last time that I fertilized plants in the garden. When I first started this garden I was in a rush for plants to fill in, so I fertilized regularly for a few years, but not since (maybe twenty years). I watch the color of foliage, and if plants would look off color I’d fertilize. Clay soils are typically rich in nutrients, and if pH is not too low these are usually available so that fertilizer is rarely needed. Some parts of the garden get an annual top dressing of leaf mulch, but most of the garden gets nothing.

      There are plenty of old varieties of azaleas that flower in late summer, though your gift azalea is likely to a florist type that might or might not be cold hardy. Lots of azaleas send out sporadic late summer or autumn flowers, but others are true repeat bloomers. I recall seeing the old azalea ‘Watchet’ flowering in October long before Encores were introduced.

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