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It’s prime time for perennials

Elizabeth Huwe/FOCUS Most spent flowers, such as these lilies, should have dead buds removed, but not be fully trimmed back until after a hard frost, said Jodie Ramsay. Perennials need to keep their leaves in order to store energy to last through the winter and grow back in the spring.

As the daylight hours continue to last for less of the day and poison sumac leaves change to deep burgundy, it is becoming more obvious that autumn is on its way. Early fall can be a great time to work with perennials in the garden.

“Most things can be transplanted at any time, with a few exceptions,” said Jodie Ramsay, half of the ownership team at Jean’s the Right Plant Place in Perham. “You don’t want to transplant something when it’s flowering. You don’t want to do it when it’s really, really hot.”

For some plants, transplanting in the spring may be easier because they will not have grown as much, said Ramsay. “But, as long as you give it enough water and you get enough of the root mass, you can pretty much do it any time.”

Coneflowers, and other plants with long tap roots, are also best moved in the spring.

Julie Schroer, the second half of the Jean’s ownership team, said garden peonies and irises are two perennials that do best when moved in the early fall. These plants should also be trimmed back in the autumn, but not immediately before or after transplanting.

“Any fall blooming things, like sedums, asters, mums… Those you probably don’t want to mess with now because you’re going to disrupt their blooming this year,” said Schroer.

“Starting now, it’s especially important for people – if they are transplanting – to use rooting fertilizer,” said Schroer. “Not Miracle-Gro in the hole, which can kill them.”

Instead, she explained, rooting fertilizer encourages extra root growth to help the plant establish itself in the new location before it gets cold.

When digging up a perennial, in order to get most of the roots, the pair recommends digging about a foot deep and as wide around as the plant’s leaves reach. For shrubs, dig deeper.

“Most plants have about as much root mass as they do above ground mass,” explained Schroer.

Ramsay and Schroer said now is the time of year to stop using regular fertilizer.

“You don’t want the plants to be making a lot of new leaves, new flowers,” said Ramsay. “You want them to start thinking about going dormant and sending the sugar to the roots instead.”

“If things are starting to look really peaked this time of year, that’s actually good for perennials,” said Schroer. “That means they’re getting ready for winter.”

Another garden task that can be done in the early fall is pruning, with a few exceptions.

“Lilacs set their flowers for the next year right after blooming,” explained Ramsay. “So, you have a very short window when you can prune lilacs.”

“Trees are supposed to be pruned in winter or really early spring,” added Schroer, this includes evergreens. “They’re supposed to be dormant.”

While pruning can be done now, Schroer said that cutting back perennials should only be done after the plant has died back on its own.

“It’s got to freeze hard,” she said. Only after that freeze should cutting and mulching be done.

In other words, don’t rush plants in getting ready for winter. Just like us, they’re just trying to soak up as many rays as they can to make it through to next year.