“Mudding In” and other planting tips

It was in 2016 when I heard the term “mudding in” at a garden club meeting—and I haven’t heard it or read it since. It sounded odd, even made-up, but coming from a Master Gardener, “mudding in” demanded some research, which I did. Yes it’s for real. Likely a British thing, but a thing nonetheless.

This unusual term describes a way to put plants into the soil, one that averts problems associated with traditional planting techniques. Whether you’ve got seedlings from a nursery pot (as shown in this photo essay), large perennials, transplants from another site, shrubs, or containerized trees, mudding in will:

If you’re moving a plant from one area of your garden to another with the same soil texture, there’s no need for this technique. But if you’re moving plants from an area where the native soil texture is different than the soil in your intended new spot, mudding-in will lower the risk of complications.

The process starts with removing most of the soil (or potting mix) around the roots, but it’s more than just bare-rooting. Here’s a short summary of the steps.
1) prepare planting holes by filling with water and allowing to drain
2) bare-root the plant (remove soil or potting mix/media from around the roots)
3) set the plant and re-fill the hole with water
4) gradually put back the soil removed and agitate to create ‘mud’
5) tamp and re-water

For many years I’ve been using this mudding-in technique for all my potted seedlings as well as any purchased or gifted plants. And I teach it to fellow volunteers at planting bees.

Recently, when looking for online resources to prepare a webinar, I found very little useful material on mudding-in. There were no text-based guides and the video guides were mostly incomplete, inaccurate, or too commercial.

So here’s a photo-essay I hope you’ll find helpful. Most of the photos are from my new garden, taken by my husband who, with better lighting and a less-finicky boss, is quite a good photographer.

Step One: Choose your site and check the weather

In this demonstration I’m putting seedlings into a nursery bed as a temporary winter home. But for long-term plantings you’ll want to choose the site carefully, taking into consideration the hours of sunlight, the soil texture and moisture, the species’ mature height, width, and form, and other cultural requirements.

Start with soil that is not freshly turned or cultivated. Wait for a rain, or (a day or two in advance) put the sprinkler on the area to reduce the size and number of air pockets in the soil. You want it to settle before planting day, to ensure that new seedlings remain at the depth they were planted.

If possible, choose a day that’s not blistering hot or relentlessly sunny. Aim to reduce the stress on your newly planted seedlings by working during a cool part of the day, under cloud cover if possible. If sun and heat are unavoidable, have a lawn chair or umbrella (or something similar) on hand to provide shade for your plants.

Have your plant markers labelled and ready to go. Did you add this species to your list / garden inventory? No? Then do it now!

In the photos you’ll notice I’m using a large bowl to hold the mix removed from the roots. In my garden, all peat-based media is saved for re-use, but you may want to re-purpose yours as topdressing. In addition to a container for potting media, a bucket of water and a full watering can are necessary. You may also need your garden hose.

Put your plants somewhere cool and shady while you prepare the hole.

Step Two: Prepare the Planting Hole

Clear the area of any mulch, including fallen leaves. Just move it aside so you can easily replace it later. Now dig the hole. How deep? Aim for the height of the nursery pot.

Pay attention to where you put the soil you remove—you’re going to be back-filling with it. The soil you remove from the hole (the backfill) is the soil you put back. I like to pile it next to the hole but you may want to put it in a tub or container, especially if the area was mulched.

Do not add fertilizer, compost, or any other amendments to the planting hole. These aren’t necessary and they can interfere with normal root growth. Just like your 24-year old nephew who lives in the basement gorging on snacks and video games, your plants should not be encouraged to hang around. Those roots need to get out of the basement and into the wider world. Help them find what they need in the surrounding soil—don’t turn that planting hole into a hideout by filling it with cushy, amended soil.

Metaphors aside, research has “not demonstrated any benefit to the perennial whose soil is amended. In fact, native soils provide enough nutrients to support sufficient perennial growth.” Read more about amending soil at planting time on the UCANR (University of California) web site.

When the hole is dug, fill it with water. and wait for it to completely drain. This could take a while, especially if you’re in clay.

Step Three: Prepare the Plant

If your timing is right, the roots will just be peeking through the pot’s drainage holes. Remove the plant from the pot and assess the roots. You can tease out roots out with your fingers or a chopstick or your favourite small, blunt instrument.

If the roots are pot-bound you’ll need to set them free. Use a clean, sharp tool—secateurs or a knife—to cut and pry the roots away from the compacted pot-shaped mass they’re trapped in. Try making three or four vertical slices down the sides, about 1/2″ deep. Combine this with a slice off the bottom if necessary.

With a large or severely pot-bound plant you can ‘box cut” the root mass, using a technique supported by research on containerized trees. Or you can “butterfly” the roots: make two perpendicular cuts from the bottom to about mid-way up the root mass. Then spread out the resulting four ‘wings’ to expose the inner roots.

The goal is to end up with roots loose enough to allow the surrounding mix to be either knocked off or washed off. Don’t worry about “fragile roots”. They “respond to pruning in much the same way as the crown: pruning induces new growth“.

Now we bare-root the plant by removing the potting mix. If your plant has woody roots (like my Amsonia in the photos) this part will be easy—just tap the roots gently with your hand or your trowel. Don’t be too precious. The entire root mass does not have to be squeaky clean. (Unless you’re dealing with invasive jumping worms, but that’s another article.)

If your plant is uncooperative with the gentle treatment (for example, if it is pot bound, has dense, fibrous roots, or is in a heavy bark-based mix) you may need to use water to bare-root the plant. Sometimes it’s enough just to swish and massage the roots in a bucket of water. Other times you’ll need to use a garden hose to direct a strong stream of water at the roots. This could get messy but eventually you’ll end up with a root ball that is mostly roots. Reserve the water-jet treatment for robust roots in a 4″ pot or larger. The roots of tiny seedlings will be damaged with rough handling.

Setting the plant

Now we’re ready to plant. Fill up your watering can and have it close. Place your bare-rooted plant in the hole and hold it upright with one hand. With the other hand, slowly fill the hole with water while you agitate the roots. When the hole is about half full, start adding the soil you removed to create a slurry or a thin mud (see video linked below). Keep adding soil and “mudding in” the roots to remove air pockets from the planting hole. As you add soil and the water drains, position the root crown so it’s level with the surrounding soil. Once the water has completely drained, raise or lower the plant if necessary.

Now gently press with your hands (not foot) to firm up the soil around the stem. Top with compost if you like, and water again. Replace the mulch, keeping it several inches away from the stem all around. Go easy on the mulch—an inch is enough. Place your plant label now, while the soil is soft. If there’s no cloud cover, create some shade with a lawn chair or something similar. I like to use a mesh waste-paper basket from the dollar store, which allows air circulation as well as long-term, 360-degree protection from the mid-summer sun and bunnies.

Check your plantings regularly. Water the soil if it dries out. Keep your shade structure in place as long as necessary, until the plant shows signs of fresh growth.

With practice you’ll find yourself mudding in all your plants and, over the years, you’ll likely develop your own ways to streamline the process. Mudding in helps gardeners, especially novices, confidently launch their plants into the world. And it will help avoid feelings of disappointment and guilt over having killed a new plant. That alone is worth the extra time and effort, don’t you think?

(click the image below to view a 30-video)