By Clarisa Diaz, seasonal gardener at McAlpin Farm and Cassie Banning, Director of Farm & Gardens
As the winter months loom, there are a few things gardeners can do to prepare for next spring. One of them is preparing pea brush for staking, as we do at the Land & Garden Preserve for the annual and perennial plants at the Abby Aldrich Rockefeller Garden, Thuya Garden, and more recently in the farm field at McAlpin Farm. Staking provides support for plants to grow upright, keeping blooms lifted. In a vegetable garden, staking helps stems to grow properly and crops to ripen.
Pea brush is a method of staking using natural materials that is more environmentally friendly than manufactured wood, metal, or plastic. Brush staking also provides an artistically sculpted aesthetic, cut neatly to stand up around plants in a garden.
The pea brush method originated in old English gardens to hold up vining pea plants, hence the name. Cuttings from any species of tree or shrub with dense branches can be used for staking. It is a popular technique in estate gardens in England.
At the Preserve, we gather young gray birch trees (Betula populifolia), one of the first fast-growing succession trees in blueberry fields in this part of Maine. If left to grow, these trees can turn a cultivated field back into a forest. We harvest the trees after they have gone dormant in early winter, late November or early December for us. We have been lucky to work with the same homeowner for many years who allows a large team of staff to harvest trees from their blueberry field each year, a kind of symbiotic relationship in which we both benefit.
We recommend using brush from locations where you are already doing thinning or pruning. In your home garden, you can use branches from trees found on your property. Apple branches from your spring pruning work well. Any deciduous tree branch is lovely, even if they have less side branching. Enjoy getting creative with your staking choices!
At the Abby Garden, most of the brush is installed so that as the plant grows, it is hidden and not apparent to visitors. This is very precise and intentional for the clean blooming aesthetics of the garden, but you can decide how much precision you want in your garden. For the home gardener needing a quick fix for a plant that is falling over, finding a fallen branch to use as a rough stake will do.
At Thuya Garden, brush is cut in a similar ornamental way as at the Abby Garden but with more utility to serve the needs of plants as they grow. Brush at Thuya is more visible than at the Abby Garden. It is added to prop up leaning plant stems after they are fully grown. Letting the brush be more visible aligns with the natural rustic aesthetic of the garden and surrounding woodlands.
At McAlpin Farm, since the plants are not publicly facing, the pea brush is purely utilitarian and clearly visible in a more traditional sense, as it would be in most home gardens.
Below is a how-to for the home gardener wanting to use a more sustainable staking technique in their garden. Find a new purpose for that branch yard waste by following this visual guide as we cut a piece of pea brush.
Step 1: Selecting the pea brush
Branches that are one to six feet can be used to cut brush. To cut a piece of brush, locate the portion of the tree with thickest branching and a solid stem branch that will not bend when the plant leans on it. If you can bend the pea brush you have cut, the plant will bend it when saturated with heavy rain.
Step 2: Making the angled cut
At least two to four inches of your pea brush branch will need to be stuck into the soil. To make this easier to do, an angled cut is ideal. You may also need to clean up the bottom of the branch by cutting off branches that will be in the way when sticking the branch several inches into the ground.
Step 3: Determining the height
How do you pick the right height brush for your plants? Optimally, pea brush will be two-thirds the height of a plant when it is fully grown. At the Preserve we use brush as short as one foot tall and as high as six feet tall depending on the plant height.
Measure from your angled cut at the base to your desired height to see where to make your final cut along the top of the branches. Preserve gardeners attach wooden measuring sticks to a movable base so they can hold up the branch with one hand in line with the measurement stick as they make their cuts.
Bundle all those branches together in your hand just below the desired height. Use pruners to make a straight cut above your hand. When you let go, you will have a uniform piece of pea brush with an angled cut at the base, and dense branching at the top.
A common mistake is to cut away additional branches below the desired height. Removing more branches will result in a less effective brush. The perfect pea brush branch is very dense; all those side branches will work harder to hold up the plant.
Tall heavy perennial plants like sunflowers (Helianthus sp.), kamchatka meadowsweet (Filipendula kamtschatica), and garden phlox (Phlox paniculata) at the Abby Garden require cutting four- to six-foot tall brush (with ~1 foot pushed into the soil) to hold up a five- to seven-foot tall perennial in full flower. A taller piece of pea brush from a small tree will naturally have a thicker diameter which is what you want to give stronger support.
For shorter plants like snapdragons (Antirrhinum majus), mayweed (Matricaria sp.), bush violet (Browallia sp.), and petunias (Petunia hybrids), a smaller size of brush is appropriate because they do not need as much support. The branch circumference should be no smaller than the circumference of a pencil. Remember if you can bend it, so can the plant!
Step 4: Installing the brush
We like to install the brush as the plant is growing, so at maturity the plant grows around and through the brush, helping to hide it. Our goal is to provide support around each plant in the plant clump that is being brushed. For example, in a snapdragon clump with 10 plants, each of the inner plants will have brush on four sides.
Plan to install the pea brush at least two inches to two feet away from the stem of your plant, depending on the plant height and how much support they need to stand upright. For shorter plants use the two-inch rule of thumb, for mature taller plants that have stems two to three feet high, install your pea brush one to two feet from the base of the plant.
It can be tricky to install taller brush deep enough in the soil but be sure at least four to six inches or more of your brush is in the soil. You may need to carefully tap it in with a mallet. With a shorter piece of pea brush you should be able to push it into the soil by hand. Grab the base of the brush and push down. If you have trouble, the soil may be compacted.
You can give your freshly installed pea brush a light test to see if it will hold up. Gently push on one side. If it moves easily, you should sink it into the soil a bit more.
In preparation for the spring, you can cut brush through the winter. We like to organize the different brush heights into different piles or bins. Cutting brush is a great way to be outside on a sunny winter day (with no wind) as you wait for spring seedlings in anticipation of planting, your staking brush will be ready to go.
By sharing our expertise at the Preserve, we hope you will find some inspiration and try it out. Happy pea brush cutting!
All illustrations by Clarisa Diaz