Bare Root Perennials
Bare root perennials are typically dormant plants with soil removed from the roots. They are field grown one+ year and harvested. Once the plants are dug, the tops are trimmed to approximately 1 inch from the crown, exceptions include evergreen perennials such as iberis, lavender, dianthus, Phlox subulata and yucca. Bare root perennials are far less prone to injury during shipping than potted plants.
Bare root perennials generally are significantly larger than those grown in plug form. With their larger size, the plants have more vigor and quickly develop more shoots or branches than smaller sized plugs. Bare root perennials tolerate cold soil and air temperatures better than tender plants. Most can be planted when soil and air temperatures are above 55 degrees. Bare root perennials can be started in pots if the soil is not warm enough. Establishing bare root perennials in pots, with potting mix, should ensure the plant develops root systems and top growth sooner.
Upon receipt, it’s important to check bare roots. While plant roots vary (i.e., wiry and thin, dense and fibrous, or thick and fleshy), roots should not be dry and brittle, nor soft and mushy. They should be firm, relatively dry, and, for most types, light brown in color. If roots are broken or damaged, snip them off. Since most plants have been packed for cold storage in advance, the appearance of light surface mold is not unusual. This is generally harmless and will not affect plant performance. A preventative fungicide is usually unnecessary unless the variety is prone to fungal diseases.
Plant As Soon As Possible. Soak roots in water for one hour before planting. This helps plants establish quicker. If you cannot transplant the roots immediately, mist roots lightly, repack them in the shipping medium and store plants in a cool, 35-40 F area, hopefully for no more than a few days.
There are three major types of perennial plant roots: fibrous roots, taproots, and rhizomes.
- Fibrous roots are a mass of thin, branching roots that grow from the base of the plant. They are often found in grasses, wildflowers, and other plants that need to spread quickly and easily. Fibrous roots are not very good at storing water or nutrients, but they are very efficient at absorbing water and nutrients from the soil. Examples are Grasses, Ferns, Hostas, Phlox and Daylilies
- Taproots have a long, thick root that grows straight down into the soil. Taproots are often found in plants that need to access deep water or nutrients. Taproots are also good at storing water and nutrients, which can help the plant survive during dry periods.
- Rhizomes are horizontal underground stems that grow along the surface of the soil. Rhizomes can produce new shoots and roots, which allows the plant to spread quickly.
General Planting Guidelines (does not apply to all perennials)
- For Fibrous and Tap Roots dig a hole twice as wide and at least several inches deeper than bare roots. Mound soil in the hole center, set the roots on top of mound, spreading them evenly around. Adjust the planting depth so that after the hole has been backfilled, the crown of the plant will be even with or just slightly under the soil surface. Water deeply so soil is saturated. Most Fibrous and Tap Roots Plants Crowns (where roots meet the stem) should be at or just below the soil surface, with “Eyes” (or new shoots) pointed up.
- Planting most Rhizomes would be similar to Fibrous and Tap Roots, though typically holes are not as deep, and rhizome maybe only be partially covered.
If planted in the spring, fertilize new plants twice during the first growing season: once after several sets of new leaves appear and a second time in midsummer. Liquid fertilizer, diluted to half strength, is recommended.
Plant placement tips:
- Astilbe - Plant astilbe so the crown of the plant sits just below the soil line.
- Buddleia - Plant so the crown is at least an inch above the normal soil level. Mound some of the soil up around the crown to create a small hill that slopes away from the plant to assist water drainage.
- Clematis - Dig a hole that is deeper than the root ball, and then position the plant’s crown about 2" below the soil line.
- Convallaria - Dig a hole deep enough for the roots and situate the plant with the crown about an inch below the soil surface.
- Dicentra - Place the crown of the plant about 1” below the surrounding soil.
- Hemerocallis / Daylilies - Set the daylily in the hole with the crown of the plant is 1” below the soil line.
- Hostas - Position the crown 1” below the natural soil line.
- Iris - Plant the crown about an inch below the soil surface. When planting bearded iris, the rhizomes should be positioned horizontally and remain partially exposed to the sun. For other types, position the crown of the plant about 1½” below the soil surface. Bulbs should be planted 4 to 5” deep, depending on type.
- Kniphofia - Position the crown at or just slightly below the soil line. If the crown is planted too deeply it will be vulnerable to rot.
- Peonies - Set peony root in the hole so the eyes (the growing tips) are positioned no more than 1” below the soil line. When peonies are planted too deeply, the plants will grow but may refuse to bloom. Cover the root with soil and water as needed.
- Phlox - Place the crown at the soil line.
Most, but not all, perennials prefer fertile, well-drained soil. Unless noted as a bog plant, good drainage helps keep root systems healthy. If looking for perennials in wet, dry, or poor soil growing conditions, there are plenty of appropriate choices.
Remember that new plantings most likely need to be watered in year 1 or until they have reestablished a good root system. After the first year, most perennial root systems will be sufficient for recommended conditions, especially if the soil surface is mulched to help retain moisture.
The best times to plant bare root perennials is in the spring (after last hard frost) or fall (30 days before first hard frost), when plants are either coming out of or going into winter dormancy. Establishing new roots is also easier when the air is cool, and the ground is moist.
