Goldenseal (Hydrastis canadensis) and black cohosh (Actaea racemosa) share the same wild home, so one bed can suit both. You build a raised pocket of forest soil in deep shade and plant root pieces in autumn. Then you keep it mulched and wait. Drainage is the point that decides success. Both plants love moisture, and both rot in soil that stays wet.
What you need
- A site with about 70 to 80 percent shade, under hardwood trees or a built shade frame
- Nursery-propagated rhizome pieces of goldenseal and black cohosh
- Leaf mould (fully rotted leaves), plus compost if leaf mould is short
- Rot-resistant boards or logs to edge the bed
- A garden fork, spade, rake and hand trowel
- Shredded hardwood leaves for mulch
- Shade cloth or wooden lath with posts, if you have no trees
- A soil pH test kit
- Plant labels and gloves
When to build and plant the bed
Build the bed in late summer or early autumn. The soil is dry enough to work, and the fill has a few weeks to settle before planting.
Plant rhizome pieces in autumn, once the tops of the plants have died back. A rhizome is a thick underground stem that stores food and carries the buds. Dormant pieces suffer little shock. They grow new roots in the cool, damp soil before the ground freezes. Aim to finish planting about four to six weeks before hard freezes begin. Early spring, before growth starts, is the second choice.
Both plants are hardy in USDA zones 3 to 8. In zones 3 and 4, plant early in autumn and mulch deeply, so pieces root before the freeze. In zones 7 and 8, choose your coolest, deepest shade, and plan to water through summer.
Step 1: Find or build deep shade
Aim for about 70 to 80 percent shade. On the ground, that looks like dappled light with small moving sun flecks, and no long spells of direct sun. Mixed hardwoods such as maple, tulip poplar, oak, hickory and beech give this shade naturally. Their leaves also supply your mulch each year. Avoid ground under conifers, and avoid shallow-rooted trees that leave the soil bone dry.
A north-facing or east-facing slope is ideal, because it stays cool and sheds water. The north side of a building can work, provided the soil drains and is not packed with rubble.
No trees? Build the shade instead. Set sturdy posts and stretch shade cloth rated at about 70 to 80 percent over the top. Wooden lath nailed with gaps between the strips does the same job. Put the cover at least 7 feet (2 m) high, and leave the sides mostly open. Air must move through, because still, humid air invites leaf disease. Take shade cloth down for winter where snow is heavy, since the weight can collapse the frame. Put it back before the leaves emerge in spring.
Step 2: Check the drainage
Test before you build. Dig a hole about 12 inches (30 cm) deep and fill it with water. Let it drain, then fill it again and watch. If the second fill is gone within a few hours, drainage is good. If water still stands the next day, the site is too wet as it is.
You can fix a slow site in three ways. Move the bed upslope, raise it higher than planned, or do both. Do not dig a pit into clay and fill it with rich soil. The pit acts like a bathtub and drowns the roots in winter.
Test the pH while you are there. Both plants prefer slightly acidic soil, roughly pH 5.5 to 6.5. Most hardwood sites fall in that range already. If yours is far outside it, pick another spot rather than fight the soil for years.
Step 3: Build the raised bed
Keep the bed no more than 3 to 4 feet (about 1 to 1.2 m) wide. You need to reach the middle without stepping on the soil. Any length works. Run it across the slope, so rain soaks in rather than racing along it.
Rake the leaf litter aside and save it. Clear weeds and vines by hand. Loosen the ground underneath to about 6 to 8 inches (15 to 20 cm) with a garden fork. Work between tree roots rather than cutting them. Leave any root thicker than your thumb alone. Never use a rototiller under trees.
Edge the bed with rot-resistant boards or with logs laid end to end. Logs look right in a woodland and rot slowly into the soil. A finished height of 6 to 8 inches (15 to 20 cm) above the surrounding ground is enough. Avoid piling soil against tree trunks, and keep the bed a few feet away from them. Deep fill over a tree's root flare can harm the tree.
Step 4: Fill with leaf mould
Mix the fill from roughly equal parts of leaf mould and the loosened native soil. If your soil is heavy clay, add more leaf mould, along with some coarse sand or fine pine bark to open it up. If leaf mould is short, make up the volume with well-rotted compost. Fresh manure and strong fertilizer are both wrong for this bed. They push soft growth and can encourage rot.
Fork the mix together, fill the frame, and rake it level. Mound it slightly in the middle, because it sinks as it settles. The finished soil should be dark and loose. Squeeze a handful. It should hold together briefly and then crumble.
Water the bed well and let it settle for a week or two before planting. Top it up if it drops a lot.
You can make your own leaf mould for later years. Pile autumn leaves in a wire bin, wet them, and leave them for one to two years. Shredded leaves rot faster than whole ones.
Step 5: Plant the rhizome pieces in autumn
Buy your stock from a nursery that propagates its own plants. Each piece needs at least one visible bud and some fibrous roots. Goldenseal pieces are small, knotty and bright yellow inside. Black cohosh pieces are larger, dark and knobbly, with fat pale buds.
Do not dig goldenseal or black cohosh from the wild. Both have been over-collected for the herb trade, and goldenseal is protected or listed as at risk in many states. Buy nursery-propagated rhizomes or plants, and check your state's rules before you harvest or sell any root.
Plan the layout first. Black cohosh grows tall, with flower spikes that can reach 4 to 6 feet (1.2 to 1.8 m) or more. Put it along the back or the center of the bed, 18 to 24 inches (45 to 60 cm) apart. Goldenseal stays low, usually under 14 inches (35 cm). Plant it along the front and edges, 6 to 12 inches (15 to 30 cm) apart.
Set every piece with its bud pointing up, 1 to 2 inches (2.5 to 5 cm) below the surface. Spread the fine roots out and firm the soil gently. Wear gloves if your skin is sensitive, and wash your hands afterward. Water the bed thoroughly. Label each group, since nothing shows above ground until spring.
Step 6: Mulch with leaves and protect from slugs
Cover the planted bed with 2 to 3 inches (5 to 8 cm) of shredded hardwood leaves. In zones 3 to 5, go a little deeper for the first winter. The mulch holds moisture, feeds the soil as it rots and stops frost heave. Frost heave is freezing and thawing soil pushing roots up to the surface. In early spring, check that the layer has not packed into a solid mat. Fluff it or thin it a little over the goldenseal, so the shoots can push through.
Damp leaf mulch also shelters slugs, and slugs love tender new shoots. Start checking as soon as growth appears. Go out after dark with a flashlight and pick them off by hand. Lay a board on the soil as a trap, and clear the underside each morning. Pull mulch an inch or two (2.5 to 5 cm) back from emerging crowns for a few weeks. If you need bait, choose iron phosphate pellets. Follow the label, use them sparingly, and store them out of reach of children and pets.
Water during the first two summers whenever the top inch (2.5 cm) of soil dries out. Water at the base of the plants, in the morning.
Step 7: Leave the bed to establish
Now comes the hard part, which is patience. In the first spring, expect small plants and perhaps a few no-shows. Some pieces sit for a season before they send up a shoot. Goldenseal often dies back early in a dry summer. That does not mean the root is dead.
By the third year the difference is clear. Goldenseal spreads into a low mat, and black cohosh forms a solid clump and begins to flower. Roots of either plant generally need at least three to five years before any harvest or division makes sense. Resist the urge to dig and check on them.
Both roots carry a long folk history. Anthony Cavender's Folk Medicine in Southern Appalachia records that mountain families gargled goldenseal root tea for sore throats. Black cohosh root appears among the plants they used for menstrual complaints. This is reported as history only. This article is not medical advice. Both plants belong to the buttercup family, which contains many irritant and toxic species. Do not make home remedies from them. Talk to a doctor or pharmacist before using any herbal product. Goldenseal in particular is widely advised against during pregnancy.
Common problems
Rhizomes rot over winter
Pieces that turn soft and dark sat in wet soil. Poor drainage is the usual cause. Mulch piled too thick and soggy over the crowns is another. Raise the bed higher, mix in more coarse material, and replant healthy pieces on a slight mound. Keep mulch to the recommended depth.
New shoots vanish or leaves are full of ragged holes
Slugs and snails are feeding at night. Look for silvery slime trails to confirm it. Hand-pick after dark, set board traps, and pull mulch back from the crowns until the leaves toughen. Seedlings and first-year shoots are at the most risk.
Leaves scorch, bleach or die back in midsummer
The bed gets too much sun, too little water, or both. Brown, crispy edges on black cohosh point to dry soil. Pale, washed-out goldenseal leaves point to strong light. Water deeply and add mulch. Rig temporary shade cloth, or plan a move to deeper shade in autumn.
Leaves develop brown spots and collapse early
Leaf blights thrive in still, damp air and crowded plantings. Goldenseal is more prone to them than black cohosh. Remove spotted leaves and put them in the trash, not the compost. Open the sides of any shade structure, thin crowded clumps in autumn, and water the soil rather than the foliage.
Nothing appears in the first spring
Do not dig yet. Gently brush back the mulch and feel for a firm bud just under the surface. A firm piece is alive and may simply be slow. Replace the mulch and wait another season. Replant only where pieces have gone soft or disappeared.
What to do next
Renew the leaf mulch every autumn, and top up the bed with leaf mould as it sinks. After four or five years, lift a few crowded goldenseal mats and black cohosh clumps in autumn. Split them into pieces with a bud each, and replant them at once to extend the bed.