Want Free Plants? Catch the Prime Moment to Propagate All These Popular Garden Perennials and it’s So Easy

There’s a magical window of time as spring nears that’s just perfect for making new plants. Catch it, and propagating free plants is a doddle! Lots of our favourite perennial plants – from asters to coneflowers and ferns to hostas – can be divided in early spring, and it’s simple to do, even if you’re a beginner gardener, just as long as you time it right.

That perfect moment is easy to recognize once you know what to look out for. It happens when the ground has thawed and dried out a little, and your plants are just beginning to burst back into life. Divide at this point, and the new plants will respond exceptionally well because their recently dormant roots are full of energy, so they’ll quickly settle into their new homes and grow strongly.

Exactly when this window arrives will depend on your USDA zone. In south or west zones (7–10), that’s likely to be in February, a little later in March for north or midwest zones (3–6), or even April in the coldest areas. Whichever zone you’re in, choose a mild, dry but cloudy day to divide, so exposed roots don’t dry out quickly.

Why You Should Divide Perennials

For a start, you can make plants for free! There are plenty of other benefits, too. Division keeps perennials vigorous and healthy, as it gives congested roots space to stretch out and find food and water. It also creates more airflow above ground, which can help reduce common fungal diseases such as mildew. It’s a great way to reinvigorate older plants, or bring an overgrown plant back into shape, too. For most perennials, dividing every 3–5 years is a smart move.

What to Divide in Spring

As a general rule, summer-flowering plants are best divided in spring (or autumn), but wait until summer or fall to divide spring-flowering plants.

• Late-summer and fall bloomers are the prime candidates for early spring division, such as Aster (Michaelmas daisy), bee balm (Monarda), coneflower (Echinacea), Phlox, Black-eyed Susan (Rudbeckia) and stonecrop (Sedum).
• Daylilies can be divided in early spring, as soon as shoots appear.
• Hostas, too, respond well. Wait until the eyes (buds) emerge, but act before the leaves fully unfurl.
• Ornamental grasses that are congested or have a hollow center should be divided once you see new blades emerging.
• Ferns are best divided when the plant has woken up and new fiddleheads have emerged.
• Snowdrops can be split immediately after they’ve finished flowering.

The Fail-Safe Guide to Dividing

A day or two before you plan to divide a plant, water it thoroughly. This will ensure it’s fully hydrated, which reduces transplant shock. Next, check the soil: you should only divide if the soil is workable, and not frozen or soaking wet.

All good? Use a garden fork to gently lift the plant from the ground, loosening the soil all around it first to keep as many roots as possible intact. Now you need to divide the plant into sections, making sure each clump has a healthy amount of roots and at least three shoots. The best division method depends on the plant type:

• If the clump is large and fibrous, use two garden forks back to back to lever it into two sections, and repeat as needed.
• If the clump is too solid for the two-fork method – perhaps with a woody crown or fleshy roots – use a knife or sharp spade to slice through.
• Smaller, looser clumps can often be gently prised apart into smaller sections; levering two hand forks back to back can be a useful technique.
• Some plants create baby plantlets around their outer edge which are easily separated.

Plant the new sections immediately, at the same depth, and water well to settle the soil around their roots and eliminate any air pockets.

Essential Tools for a Great Result

And that’s it! Treat your babies as you would any newly-added plant, watering regularly to keep the soil evenly moist, until they’ve settled into their new home and are growing well. A layer of mulch around the base of the plant will help retain soil moisture.