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Heuchera is container-grown and can go in at almost any time the ground is workable, but the two good windows are as growth restarts after winter and in early autumn while the soil is still warm. Spring planting gives the plant the whole season to root before its first winter, which matters in cold gardens where an unrooted plant gets heaved straight out of the ground by frost. Autumn planting suits mild gardens, where warm damp soil and cool air are ideal rooting conditions.
Avoid planting into the middle of summer heat. The root system is shallow and a newly planted heuchera has no reserves to draw on; if you must plant then, be prepared to water two or three times a week and shade the plant through the afternoon until it has taken hold.
Before anything else, knock the plant out of its pot and look at the root ball. You are checking for two things: white active roots rather than a solid mat of brown, and no fat white C-shaped grubs in the compost. Vine weevil arrives in bought plants more often than by any other route, and the moment before planting is the only convenient time to find it.
Prepare an area, not a hole
Heuchera roots run sideways in the top six to eight inches (15-20 cm) of soil, so digging a deep narrow hole and filling it with good compost does nothing useful. Improve a patch about eighteen inches (45 cm) across instead: fork over the top spit, mix in a couple of good handfuls of garden compost or leaf mold, and on heavy ground add grit as well. What you are trying to produce is soil that holds moisture in summer but does not stay saturated in winter.
On clay or anywhere water lies after rain, plant on a low mound so the crown sits two or three inches (5-8 cm) above the surrounding level. Winter wet at the crown is the commonest cause of losing a heuchera in its first year, and raising the planting position is a more reliable fix than any amount of grit mixed into a hollow.
| Item | Specification | Why |
|---|---|---|
| Prepared area | 18 inches (45 cm) across, one spit deep | Roots spread sideways, not down |
| Compost or leaf mold | Two large handfuls forked into the top spit | Holds moisture without waterlogging |
| Grit on heavy soil | A handful per plant, plus a raised planting position | Keeps winter water away from the crown |
| Spacing, small kinds | 12 inches (30 cm) between plants | Rosettes just touch when mature |
| Spacing, large kinds | 18 to 24 inches (45-60 cm) | Air movement reduces mildew and leaf rot |
| Planting depth | Soil level with the base of the lowest leaves | The starting point that delays crown lift |
Do not add general fertilizer at planting. Heucheras root better into moderately fertile soil, and a rich start produces soft leaves that scorch and a crown that stacks upward faster.
Setting the crown at the right depth
This is the step that decides how long you get before the plant needs lifting. Because a heuchera builds a woody stem upward year by year, whatever height you plant it at is the height it starts climbing from. Plant it high and it is sitting on a bare neck within two years.
- Tease the root ball open Loosen the outside of the root ball with your fingers and pull a few roots outward, particularly if they are circling the pot. Roots left in a tight spiral often stay in that shape and never spread into the surrounding soil.
- Find the base of the living leaves Pull off the dead brown leaf bases around the stem so you can see where the lowest living leaf stalks emerge. That point is your soil line. Anything below it is stem that should be buried.
- Set it slightly deeper than it grew in the pot Place the plant so the soil will come up to the base of those lowest leaves, which usually means half an inch to an inch (1-2 cm) deeper than it sat in its pot. Buried stem produces new roots. Never bury the growing points in the middle of the rosette.
- Backfill and firm by hand Fill in with the improved soil and firm it with your hands, not your heel. The aim is contact between roots and soil with no air pockets. Heavy treading compacts the surface and the shallow roots suffer for it.
- Water in thoroughly, then mulch clear of the crown Give each plant a couple of gallons (8-10 liters) to settle the soil around the roots. Mulch an inch (2-3 cm) deep over the root zone but pull it back a hand's width from the leaf bases so the crown is not sitting in damp material.
The first year, and what to write down
Water a new heuchera through its first summer whenever the top inch (2-3 cm) of soil is dry, even in a season you would call wet. Its roots are still confined to the volume of the original pot for the first couple of months, and that volume dries far faster than the ground around it. From the second year, established plants need water only in genuine dry spells.
Expect the plant to look ordinary in its first year and much better in its second. Some of the leaves it arrived with will yellow and go; pull them off. Flower stems in the first summer can be left or cut off, and cutting them lets the plant put everything into building the rosette and roots.
Record the planting date, the exact position, the leaf color, and how much afternoon sun the spot actually gets. Then add a single forward note: the year you intend to lift and replant it, which is three years from now. That one line is what stops a healthy plant being quietly lost to a lifted crown, because the job is easy to do and easy to forget until the plant is already dying.