Gadenin日本語Get the appOne plant, two opposite requirements
Heucheras are shelved under shade planting, and that advice loses more color than anything else people do to them. The dark-leaved kinds, the deep purples, near-blacks and bronzes, get their color from pigments the plant produces partly in response to light. Grow one in deep shade and it fades toward dull greenish-bronze, the leaves stretch, the rosette opens out flat and floppy, and it stops looking like the plant you bought.
The pale ones behave in the opposite way. Lime, chartreuse, amber, orange and peach foliage has less protective pigment in the upper leaf surface, and strong afternoon sun cooks it. You get brown papery patches on the exposed side within a few hot days, and those patches never heal; that leaf stays damaged for the year it lives.
So there is no single answer to how much sun a heuchera wants. Sort your plants by leaf color and place them accordingly. This is the most useful single decision you make about them, and it costs nothing.
| Leaf color | Light it wants | What goes wrong in the wrong place |
|---|---|---|
| Near-black, deep purple, dark bronze | Half a day of sun, morning sun plus bright afternoon is ideal | Fades to muddy green and flops in deep shade |
| Mid purple, silver-overlaid, veined | Morning sun, dappled light the rest of the day | Tolerant either way; loses contrast in dense shade |
| Lime, chartreuse, gold | Bright shade or morning sun only | Brown scorch patches by midsummer in afternoon sun |
| Amber, orange, peach, coral | Morning sun with afternoon shade | Scorches quickly; color also washes out in deep shade |
| Plain green with red or silver marbling | Very adaptable, shade to half sun | Little goes wrong; the most forgiving group |
When you are not sure, morning sun with shade from midday onward suits every heuchera reasonably well. It is the compromise position: dark leaves keep most of their color and pale leaves do not burn.
Soil matters more than light for survival
Light decides how good a heuchera looks. Soil decides whether it lives. The plant has shallow fibrous roots and a crown that sits at the surface, which means it dies from two directions: soil that stays waterlogged over winter rots the crown, and soil that bakes dry in summer kills the shallow roots outright because there is nothing deeper to fall back on.
What it wants is soil with organic matter in it that drains freely. Work compost or leaf mold into the top spit before planting, and on clay plant on a low mound two or three inches (5-8 cm) proud of the surrounding level so water runs away from the crown. Avoid the bottom of a slope, the base of a downpipe, and any spot where you know water stands after heavy rain.
The classic difficult spot is dry shade under a tree or against a wall, and heuchera is often recommended for it. It will manage there, but only if you get it established first with regular watering through its first summer and keep a mulch of compost on the surface, pulled back clear of the leaf bases. In root-filled dry soil the plants stay small and go downhill after a few years.
Containers, exposure and winter position
Heuchera is one of the best container plants there is, because it is evergreen, the rosette shape is neat, and it earns its space in winter when little else does. Use a pot at least ten inches (25 cm) across with proper drainage holes, a compost with grit or bark mixed through it, and remember that a container dries out far faster than the ground. In pots the sun tolerance drops: a plant that copes with afternoon sun in the border will scorch in the same position in a pot, because the root ball heats up and dries.
Wind and exposure are underrated. The leaves are held on long stalks and shred and brown at the edges in constant wind, and exposed crowns are the ones most likely to be heaved out of the ground over winter. A position with some shelter from a wall, a fence or neighboring planting keeps the foliage in much better condition.
In winter the plant keeps its leaves, so where you put it determines whether you see anything. Placing heucheras near a path, a door or the front of a border pays off for four or five months a year when the rest of the bed is bare. In cold gardens the winter risk is not cold itself but the freeze-thaw cycle that lifts crowns; a mulch of bark or leaf mold over the root zone, pulled clear of the leaves themselves, steadies the soil temperature and reduces heaving noticeably.
Testing a position and recording the result
The only reliable way to know how much sun a spot gets is to look at it. Check the same position three or four times during the longest days, once mid-morning, once at midday, once mid-afternoon and once in early evening, and write down whether it was in sun or shade each time. Overhanging branches and buildings make a nonsense of guessing, and a border described as shady is often in full sun from mid-afternoon, which is precisely the part of the day that scorches leaves.
Record for each plant its position and its leaf color, and then note at the end of summer whether it scorched, whether it faded, and whether it flopped. Those three observations tell you what to do the following spring: scorching means move it to less afternoon sun, fading and flopping means move it to more light, and neither means leave it where it is. Heucheras transplant easily while dormant, so a plant in the wrong place is a decision you can reverse at almost no cost.
Note the move itself, and the date. A plant that has been moved needs the same aftercare as a new one, and it is easy to forget the following summer that its roots are only a year old in that spot.