Gadenin日本語Get the appDrainage matters more than soil richness
Lavender evolved on thin, stony, alkaline hillsides with hot dry summers. It does not want feeding, and it does not want moisture-retentive soil. What kills it is water sitting around the crown and the upper roots through a cold, dark winter, which rots the base while the top still looks alive.
Test the site before you plant. Dig a hole a foot (30 cm) deep, fill it with water, let it drain, then fill it again. If the second filling has not drained away within four hours, that spot will kill lavender sooner or later. Either choose a different position, or raise the planting area.
- Raise the bed if you have any doubt Six to eight inches (15 to 20 cm) of raised soil is enough to keep the crown above the winter water table on most heavy ground. A low mound, a raised bed edge or the top of a slope all work.
- Add grit, not compost Fork a generous quantity of coarse grit or sharp sand into the top foot (30 cm) of heavy soil, roughly one part grit to three of soil. Do not add rich compost or manure. Fertile soil gives soft growth that flops, flowers less and rots in winter.
- Aim for neutral to alkaline Lavender does best between pH 6.7 and 7.5. On acid soil, work in garden lime a few weeks before planting according to the product rate for your soil type, and expect to repeat it every few years.
Full sun, and more of it than you think
Lavender needs a minimum of six hours of direct summer sun, and it repays eight or more with tighter growth and stronger scent. In part shade it stretches, flowers thinly, holds moisture in its center and becomes a target for gray mold at the base.
Air movement counts almost as much as light. A plant tucked against a fence with shrubs crowding it stays damp for hours after rain. Give each plant open air on at least two sides, and avoid planting where a hedge or wall drips onto it.
Plant high and firm, and keep mulch off the crown
Set the plant so the top of its rootball sits about half an inch (1 to 2 cm) proud of the surrounding soil, then slope the soil away from it. Planted level or slightly sunk, the crown collects water every time it rains and eventually rots at the base of the stems.
Water it in once thoroughly to settle the soil around the roots, then leave it. New lavender does not want repeated heavy watering; it wants to send roots down looking for moisture. In the first season, water only when the plant looks dull and limp in the morning, which on most soils means a handful of times.
| Detail | Do this | Why |
|---|---|---|
| Planting depth | Rootball top half an inch (1 to 2 cm) above soil level | Stops water pooling at the crown |
| Hole size | Twice the width of the pot, same depth | Roots spread sideways in the top foot (30 cm) |
| Backfill | Native soil plus grit, no compost | Rich backfill keeps roots in the hole and holds water |
| Mulch | Gravel or coarse grit, one to two inches (3 to 5 cm) | Keeps the base dry and reflects heat; bark holds damp against the stems |
| First watering | One thorough soak, then almost nothing | Encourages deep rooting instead of a shallow mat |
Never mulch lavender with bark, leaf mold or garden compost. Those hold moisture exactly where it does the most harm. Gravel, grit or coarse stone chippings are the only mulches worth using around the crown.
Spacing decides how long the plant stays presentable
Plant at the eventual width of the group you are growing, not at the size of the pot you bought. Crowded lavender stays damp in the middle, loses its lower leaves and goes woody at the base years earlier than it should.
For English lavender, allow eighteen to twenty-four inches (45 to 60 cm) between plants. For lavandins, allow thirty to thirty-six inches (75 to 90 cm). For a low hedge, close the spacing to about twelve inches (30 cm) for English types and accept that the hedge will need cutting twice a year to stay dense. In a pot, use a container at least twelve inches (30 cm) across with drainage holes you have checked, a gritty mix, and no saucer underneath.
Plant in spring where winters are hard
The best planting time is spring, once the soil has warmed and hard frost has passed. That gives the plant a full season to root out before it has to face winter, which is exactly the resilience a first-year plant lacks.
Autumn planting works in mild areas with free-draining soil, but in a cold or wet region an autumn-planted lavender spends its first winter with a small root system in cold wet soil and often does not come through. If you buy in autumn in a cold area, keep the plant in its pot somewhere sheltered and plant it out in spring.
Write down the planting date and the position of each plant. Lavender declines slowly, and when a plant starts thinning at the base in its fourth or fifth year, knowing exactly how old it is tells you whether to prune harder or to start replacement cuttings.