Gadenin日本語Get the appDecide what ground you are giving away before a single pip goes in
Lily of the valley travels by underground rhizomes, the horizontal stems that carry the fat pointed buds gardeners call pips. A single crown planted into decent soil sends runners out in every direction two to three inches (5-8 cm) below the surface, and each runner puts up a new pair of leaves the following spring. Within three or four seasons a starter clump has become a continuous mat of overlapping leaves, and nothing small enough to be overtopped survives underneath it. Hellebore seedlings, small bulbs, epimediums, primulas, self-sown ferns and anything else with a crown near the surface get shaded out first and then physically crowded out by the rhizome mesh.
It is also extremely hard to undo. Every fragment of rhizome left behind regrows, so digging a patch out means lifting and sieving the top eight inches (20 cm) of soil and then going back over the same ground twice in the following season to pull the pieces you missed. The leaves are waxy enough to shed most of what you spray at them, so chemical control is unreliable too. Plant it on the assumption that the area you give it is the area it keeps.
The right place is dry shade where nothing else works
The classic position is under established shrubs and on the shaded side of walls, hedges and buildings: places with root competition, low light and soil that dries out in summer, where most ground cover fails and weeds do not. Lily of the valley will not merely tolerate that, it will fill it and stay filled, and on that sort of ground it spreads at a sane pace rather than exploding. A narrow strip between a path and a fence, the north face of a garage, the ring of dry soil under a mature lilac or a hazel are all ideal.
Rich, moist, cultivated soil in half shade is where it becomes a problem. It runs fastest exactly where your other shade perennials are happiest, which is why so many people meet it as a weed rather than as a plant they chose. If the only spot you have is good border soil, either contain it physically or grow it in a pot instead.
Every part of it is seriously poisonous, including the berries and the vase water
Lily of the valley contains cardiac glycosides in every part: leaves, flowers, stems, rhizomes and berries. Eating it can disturb the heart rhythm, and the amount involved is small. In late summer the flowers that were pollinated ripen into coral-red berries the size of a small pea, held at ankle and knee height in the middle of an attractive-looking patch of green. That is exactly the shape and position that gets picked up by a toddler or eaten by a dog, and berries are the most common route to a real poisoning case.
The water that a picked bunch has stood in is also dangerous, and this catches people out because it looks like nothing. Cut stems leach the same compounds into the vase, so the water in the jug is a poison in its own right. Tip it down an outside drain, not into a sink where a pet bowl gets filled, and do not leave the vase where a child can reach and drink from it. Wash your hands after arranging the flowers.
This shapes where you plant it. Keep it out of the parts of the garden where small children play unsupervised, off the edges of paths and lawns where a hand naturally reaches down, and away from any run or enclosure an animal is shut into. Under shrubs at the back of a border, in a bed against a wall, or in a raised container is where the risk drops to almost nothing while the plant still does its job. If a berry is eaten, treat it as urgent and call a poisons center or a doctor rather than waiting to see whether anything happens.
There is a second, more serious version of this problem. The leaves of lily of the valley look very like the leaves of wild garlic, and foragers have been poisoned by picking one for the other. If you grow it anywhere near a patch you or anyone else forages from, that risk is worth taking seriously; the hazards guide covers how to tell them apart.
Planting the pips: timing, depth and spacing
You are almost always planting pips rather than growing plants: short lengths of rhizome, each with one or more pointed buds at the tip and a spray of thin roots underneath. They arrive dormant and they should go in dormant, from late autumn through to the point in late winter when the buds begin to swell and lengthen. Planted then, the roots settle over the cold months and the pip flowers in its first spring. Planted while in leaf, the same pip usually sulks for a season.
| Item | What to do | Why it matters |
|---|---|---|
| Season | Dormant season, from leaf fall until the buds start to extend | Roots establish before the leaves make demands on them |
| Depth | Bud tip half an inch (1 cm) below the surface, rhizome laid flat | Deep planting delays or prevents flowering in year one |
| Orientation | Rhizome horizontal, roots spread downward and outward, bud pointing up | A pip planted vertically wastes a season correcting itself |
| Spacing | Four to six inches (10-15 cm) apart for quick cover, twelve inches (30 cm) if you want it slow | Spacing decides how long the gaps stay open, not the final density |
| Soil | Any soil that is not waterlogged; fork in leaf mold if it is heavy clay | Rot is the only soil condition that actually kills it |
| After planting | Water in once, then mulch one inch (2.5 cm) with leaf mold | Settles the roots and stops the pips lifting in frost |
| Quantity | Six to ten pips for a patch a yard (1 m) square | More than that only buys you a year |
Containing it, and what to write down in the first two years
If the only place you have is next to plants you care about, contain it at planting time. Retrofitting a barrier around an established mat is far harder than putting one in first.
- Sink a solid vertical barrier to ten inches (25 cm) Rigid plastic edging, slate, or a bottomless bucket sunk into the bed all work. The rhizomes run shallow, so ten inches (25 cm) of continuous vertical material holds them. Leave half an inch (1 cm) of the barrier proud of the soil surface so runners cannot simply cross over the top.
- Use hard edges you already have A strip bounded by a wall on one side, a concrete path on another and a mown lawn on the third needs no barrier at all. Regular mowing stops the mat dead, so a lawn edge is a genuine boundary, while a gravel path or a bed of loose bark is not.
- Grow it in a container if the ground is precious A wide, shallow pot at least twelve inches (30 cm) across suits it, in soil-based compost with added leaf mold, plunged into a shady bed or stood on a north-facing step. It fills the pot in two seasons and then needs splitting, which is the point at which you get spare pips to give away.
- Walk the edge once a year In late spring, when the leaves are fully out, the boundary of the mat is obvious. Push a spade in vertically along the line you want to keep and pull the escaped runners out from the outside. Five minutes once a year holds a patch where it is; three years of neglect does not.
The first two years, and what to record
Expect very little in the first spring. Newly planted pips typically produce a pair of leaves and either one modest flower spike or none at all, and the patch looks thin and disappointing. The second spring is usually the first real display, and the third is when the mat closes. Resist the urge to add more pips into the gaps in year two; you will only be digging them up again when the original planting closes over them.
Write down three things while they are still easy to know. First, the date you planted and how many pips went in, because it tells you whether a weak second spring is a problem or simply normal. Second, the outline of the patch, either as a rough sketch with measurements from a fixed point such as a wall or a post, or as a photograph taken from the same spot each spring. Comparing that outline year on year is the only honest measure of how fast it is running for you, on your soil, and it turns the question of whether to intervene into an observation instead of a guess.