Planting Perennials Closer Together: Why More Is Better

How Far Apart Should You Plant Perennials? Closer Than the Tag Says

Most perennial tags recommend spacing that assumes you're happy to wait. If you've ever planted a single 1 or 2 gallon perennial in the centre of a 2 x 2 foot space and then watched it sit there for a few seasons, looking a little lonely, you already know the problem. It typically takes 3 to 4 years for a perennial that size to fill out and look the way it does in the photos.

With Ontario's short growing season, that's a long time to wait. Our advice: plant closer together than the tag suggests. The plant tag is not wrong; it is usually describing mature spacing. The question is whether you want to wait several years for that mature look, or create a fuller effect sooner. Instead of one perennial per 2 x 2 foot space, plant three in that same area, spaced about 6 inches apart. You'll get a fuller garden faster, and a few other benefits along the way.

Why closer spacing works in your favour

A full look now, not in year four. Three smaller plants filling a space together read as an established garden almost immediately, rather than three or four years from now. If you're the type of gardener who enjoys the payoff, not just the process, this matters.

Fewer weeds, less weeding. Bare soil between widely spaced perennials is exactly where weeds set up shop. Close plants shade that soil out and close the gaps before weeds get a foothold, which means less time spent weeding over the life of the bed.

Less mulching. The main reason we mulch new beds is to suppress weeds and retain moisture in all that exposed soil. Cover the ground with plants instead of bark, and you need less mulch to begin with, and less of it to top up in following years.

A more enjoyable garden, sooner. A bed that looks finished is simply more satisfying to walk past, sit near, and photograph. From a design perspective, repeated groups of three or more also create stronger drifts of colour and texture than single plants dotted through a bed. Waiting years for a planting to "arrive" can take the fun out of a new garden bed.

If a garden plan calls for one, plant three

Nurseries typically list spacing and quantities based on a plant's mature size, which makes sense for large shrubs and trees, but for perennials it often means underplanting. If your plan calls for one perennial in a given spot, consider three of the same variety in that space instead, at roughly 6 inch spacing. You'll fill the bed faster and get a fuller, more cohesive drift of colour and texture instead of a single small clump.

Too bushy? Just split them

One thing that puts gardeners off close spacing is the worry that plants will eventually crowd each other out. They will, eventually, and that's a good problem to have. When a perennial outgrows its spot, dig it up, split it, and use the divisions elsewhere in the garden or share them with a neighbour. Splitting an overgrown perennial is easy and satisfying, and it means you get more plants for free down the road. Compare that to the alternative, which is a sparse bed and years of staring at mulch, waiting for something to fill in.

The bottom line

Give your perennials less room than the tag suggests, not more. Plant in threes instead of ones, aim for about 6 inches between plants rather than spacing for a mature single specimen, and treat overcrowding as a future opportunity to divide and multiply your plants rather than a mistake to avoid. You'll spend less time weeding and mulching, and more time enjoying a garden that looks established from its first season.

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