Monday, May 26, 2014

Plant Root Rights and Wrongs

Despite the recent weather events, you have plants needing to go in the ground, some have been waiting a few weeks (probably the ones you purchased over Mother's Day weekend).  And until the ground dries out you'll probably wait a few more days. Hopefully you acclimated them to the outdoors out of direct contact with the pounding rain or hail (see previous post for hardening off information). This is where shade cloth and floating row covers really come in handy to protect new plantings or existing areas of your garden that you're babysitting until well established.

Root Bound 'Mini-Man' Viburnum (new plant from Fort Collins Wholesale Nursery)

So, you have your planting hole dug to the correct depth, not too deep so it drowns, just a little high is best, especially if you think it will settle a bit. I usually mix in a small amount of slow release fertilizer and a handful or two of finished compost (homemade is best if you have it on hand).  Don't mix too much of non-native soil, otherwise the plant roots won't want to leave the area. Scratch or loosen the sides of the planting hole so the roots don't hit a brick wall as they grow. The planting hole should be two to three times the width of the root ball for the roots to establish. The planting depth is usually the same depth as it was in the container. Trees are the exception (that's a whole other discussion about root flare and planting at the correct depth). 

But what if the roots are compacted in the container?

You can see from the photos that this viburnum is well established in the growing pot, not a deal breaker what so ever, this is what they do, how they grow in a small environment like a container. Often you'll see this in the garden center with annuals and other plants, even to the point where roots are coming out of the bottom of the container, again, no worries.

What to do. It's easy, you want to break up the circled roots so they will reach out into the soil and not continue playing ring around the root ball in the planting hole. Use scissors for larger plants (one gallon or larger), a knife or hori hori  The side of the plant tag is usually strong even to score the sides of smaller 2-3 inch size containers. 

In my example I used scissors and made cuts on four sides and the bottom.  Done, it's that simple. I made sure the new guy has a drip emitter going to the root area, then filled in around with my native soil and some compost.  If it's a really large plant or tree I would fill in soil gradually, then water in between soil layers, this ensures that the root ball gets completely watered in the planting hole.  Finish it off with a 2-3 inch layer of wood mulch. Native plants and rock garden plants prefer rock mulch, so adjust accordingly.

Scissors to Score or Cut Plant Roots
A Bit More Soil is Needed, then 2-3" Mulch

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