When to plant Turkish mullein?
Best month and method — Verbascum bombyciferum
Plant your turkish mullein in March, April, May, September and October — the optimal month is usually May.
You're in the planting season right now — a good moment to start.

Spacing
50 cm
≈ 4 plants
For an X m² border, calculate: X × 4 plants.
Step by step: plant turkish mullein
Verbascum bombyciferum thrives in full sun and well-drained soil, making it ideal for gravel gardens, sunny borders, and Mediterranean-style plantings. It tolerates sandy, loamy, and chalky soils but will not perform well in heavy clay or waterlogged ground. If your soil is prone to sitting wet, dig in plenty of grit or coarse sand before planting to improve drainage. Plant young verbascum in March, April, or May for establishment before summer, or in September and October to give roots time to settle before winter. Space plants 50 cm apart to allow for their eventual spread of 40–60 cm and to ensure good air circulation around the silvery foliage. Dig a hole slightly larger than the root ball, place the plant so the crown sits level with the surrounding soil, and backfill with the excavated soil mixed with a little compost if your ground is very poor. Water in thoroughly after planting to settle the roots, but thereafter verbascum needs very little irrigation thanks to its low water requirement. Avoid planting too deeply, as a buried crown can rot in damp conditions. A light mulch of gravel or grit around the base helps suppress weeds and keeps the neck of the plant dry, which is especially useful over winter. Staking is rarely necessary despite the plant's impressive height of 120–200 cm, as the sturdy flower spikes are naturally robust. Choose a sheltered spot if your garden is very exposed to strong winds, though the plant is generally tough once established.