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What perennials divide in August: why divide is necessary & what varieties can tolerate them in midsummer.

Are you currently wondering when you should divide perennials? Well, now in August is one of the best times for some perennial species. But how do you know which ones exactly? To help you out a bit, we’ve rounded up some of the species you can care for and propagate now by dividing. So roll up your sleeves, get the gardening tools out of the shed and get to work keeping your garden in tip-top shape. What perennials are dividing in August? We’ll summarize!

Which perennials divide in August – Why is division so important?

What perennials divide in August - Suitable and unsuitable varieties.

On the one hand, it’s a way to propagate your plants to help form a dense carpet of blooms. On the other hand, dividing every few years is also an important way to encourage and improve flowering. This is very much the case with cushion perennials. So this step is important for taking good care of your plants. But which perennials divide in August?

Which perennials divide in August – It depends on the flowering period.

Which time or period is the best to divide perennials depends mainly on when their blooming season is. Autumn-flowering perennials, for example, should not be disturbed in midsummer or late summer, because they are just preparing for this flowering season and need the strength for this, rather than for acclimation to the new location. Because then the plant needs strength for root formation. The same applies to perennial species that are just blooming. For them, division is best done in the spring.

So if you are wondering which perennials you can divide in August, you are left with the varieties that have their flowering season in spring and early summer. This is now over and there is another advantageous feature: these perennial varieties now have a small dormancy period in mid-summer, which provides ideal conditions for division. If you now replant the divided plants, they will subsequently have plenty of time until the colder autumn to form new roots and thus adapt to the new location.

But, as is often the case, there are exceptions. Peonies, for example, you’re better off leaving alone, because their growth continues into the fall. There are also such species that, despite their early flowering, should not be divided. For this reason, you should always check before you start dividing certain perennial species and are not sure. Now let’s move on to a few suitable varieties: What perennials divide in August?

Perennial species that tolerate (and need) division in mid-summer.

How often and how to divide iris

Which perennials divide in August - Iris has rhizomes that are cut off

Without question, the bearded iris is one of the most popular garden plants. Therefore, we are not surprised if this beauty also adorns your garden. This perennial should be divided every three to four years, and since it blooms in spring, August is also the ideal time. And this applies both to the varieties with rhizomes, and those that do not form rhizomes.

Shorten bartiris, let it dry and replant it

The bearded iris

From the so-called rhizome should have grown new ones. You can cut off the outer ones, which in the meantime have also developed healthy and strong foliage, shorten the leaves to about 10-15 cm and let the cuttings dry for a day before transplanting them again. When doing this, part of the rhizome should be out of the ground to receive sunlight.

Propagate and care for meadow iris - tips for division in midsummer


The meadow iris

Meadow iris blooms from mid to late spring and after flowering, so in August , is also the best time to divide it. This variety does not have a rhizome, but it forms new sections that you can also cut off. Before doing so, pay attention to how deep the mother plant is planted and plant the new iris plants just as deep.

Maintaining and propagating the hardy daylily by division

Daylilies are hardy and can be divided at any time

Since the daylily is a hardy plant, division is in principle possible at any time. But if you’re already dividing perennials in August anyway, you might as well go ahead with the daylily. Make sure the parts you cut off are about the size of your fist and don’t have too large of a cut, as this will make them more susceptible to damage. As with the iris rhizomes, a drying time for the cut wounds is beneficial here. You can then plant the new parts the next day.

Which perennials divide in August – These species don’t need dividing, no matter what time of year it is

Which perennials divide in August - division of daylilies possible in midsummer


  • Columbine
  • Chinese reed
  • Thistle species
  • Pasque flower
  • Prachtspiere,
  • Peony
  • Ragwort Aster
  • baby’s breath
  • Silver candle
  • Weeping heart
  • Turkish poppy
  • Forest honeysuckle

Note: The Weeping Heart can be divided in some circumstances, although it is not recommended or necessary. However, if you absolutely want to propagate your plant, be very careful when dividing, as the plant has rhizomes with very delicate roots that you must not injure (except for the cuttings, of course, which cannot be avoided, but should be as small as possible). Each new section should be about the size of a fist, and even two days to dry before you replant.