How to divide Spiderworts – and lots of other perennials

Spiderworts in their May and July glory.

by Susan Harris

The violet flowers were no more, the foliage was looking ratty, and it was time to prune these Spiderworts (Tradescantia virginiana) and prune ‘em hard.    With any luck, they’ll grow new foliage and look good again in a couple of weeks or so.   Anyway, it beats letting them look ratty for the rest of the season.

But while they have their new haircuts it’s a great time to also divide the two larger clumps in order to cover some bare ground in my perennial border and simply produce a larger, fuller mass of this perennial favorite of mine.

Newly pruned

These clumps are big enough to divide into four pieces each.

How to Divide Spiderworts, Hostas, Tall Sedums, Liriope, etc.

1. Dig up completely, as in the picture above.

2. Slice through the root mass with a knife to produce good-sized chunks. My favorite perennial-dividing knives are steak knives from the dollar store – 4 for a dollar.  They gradually get dull, so I have to buy another 4-pack every few years but it’s still the cheapest tool in the shed.  All the perennials listed above are easy to cut through but none easier than this Spiderwort, which I’d never divided before. After the first slice I declared aloud: “Cuts like buttah” (with apologies to a famous Saturday Night Live sketch).

3. Place the new divisions in the garden where you want them, then step away from those plants!  Literally – step back so you can check to make sure that’s where you want them. (This step is especially important for plants that are harder to replant – like trees and shrubs. unfortunately, it’s a step I’ve sometimes ignored it in my haste.)

4. Plant, and mulch around them.

5. Water well. In this heat, I’ll keep watering daily for a few days, then keep an eye on them for the rest of the season. Mid-summer is a terrible time to move or divide anything, but I think these guys will survive – thanks to good watering and the severe haircut they’d already received. That’ll keep them from losing lots of moisture through the leaves.

Divisions placed where I want them, before planting.

5 Responses to How to divide Spiderworts – and lots of other perennials

  1. Sue says:

    Thanks so much for this post! I’ve always wondered when to divide my liriope. Would it be better to divide them in September when it’s a little cooler?

    On a different topic, but related to moving thing things in hot summer heat: I moved 3 small crape myrtles yesterday. 2 are fine and doing well, but one has crazy limp leaves. I’ve watered it a lot – so much so that I’m trying to restrain myself for fear that it might drown.

    What should I do? Do you think it will be ok?

  2. Chris Maciel says:

    This is off subject Susan, but I need help on a problem I’m having with borers working on Monarda, Buddlea, and Agastache. The tall stems are bored through and just flop over.

    Does anyone have any ideas what would help, and when the treatment should be done.
    I’ve only read one suggestion for using insecticidal soap but I can’t see how that would help.
    Thanks.

  3. Pingback: What I’m Doing in the Garden, July Edition « Homestead Gardens

  4. Gene Sumi says:

    In response to Chris’ query about control of borers on his monarda, agastache and buddleia, the borers are likely the caterpillar borers of a moth. What this means is that there are few options for real control of them. Lindane would have been the best control, but this borer insecticide is no longer available. Systemic insecticides containing Imidicloprid which internalize the action of insect control would be fine, but the they do not work on caterpillar borers. Once the damage is seen, the damage to the plant is done. You can try to prevent new damage on unaffected plants by the application of Bonide Borer and Leaf Miner spray, which uses Permethrin as its active ingredient. The spray seeps through the bark or outer cuticle to reach the borer underneath. This may provide some control in the early stages, but it is not as effective as Lindane had been.

  5. pq says:

    I bought a set of six cheap steak knives at a church sale years ago, and i use them as garden tools, too! And here I thought I was so original. Great for slicing open bags o mulch, too.

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