Thorow-wax

Thorow-wax: how do you recognise it?

Habit

Upright plant, branching near the top, 45–60 cm tall and 25–30 cm wide.

Leaves

Round to oval, blue-green with smooth edges. The upper leaves completely encircle the stem, as if the stem grows through them.

Flower

Small umbels of yellow flowers surrounded by broad yellow-green bracts, from June to August.

Seed

Small dark fruits that ripen in late summer; on bare soil it sometimes self-seeds lightly.

Roots

A taproot: the plant dislikes being transplanted.

Flowering: June–August · Sowing: March–April and September

Why grow it?

• One of the finest fillers for bouquets, with a fresh yellow-green colour that goes with every flower.
• Lasts well in a vase.
• Flowers from June to August and attracts small bees, hoverflies and other beneficial insects.
• Easy: you sow it directly where it is to grow and it needs no fertiliser.
• A graceful, airy plant among other annuals and in a wildlife-friendly garden.

Thorow-wax: where does it grow best?

• Full sun.
• Well-drained soil: sand, loam or clay, preferably neutral to chalky.
• Dry to moderately moist; no wet feet. Soil that is too rich gives floppy stems.
• Sow in rows 25–30 cm apart and thin to 20–30 cm between plants.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

0.6 m tall, 0.3 m wide

Hardiness

Tolerates light frost (to -10 °C)

Goes well with

• Cornflower: Blue flowers against the yellow-green, in the border and in the vase.
• Field poppy: A classic cornfield combination for the same sunny, lean spot.
• Bishop’s flower: White, lacy umbels for an airy cutting bed.
• Love-in-a-mist: Delicate blue and white, in the same poor, sunny soil.
• Dahlia: Bright colours in bouquets, with thorow-wax as a fresh filler.

Thorow-wax: when and how to plant it?

1. Sow directly in situ in March–April or in September: it dislikes being transplanted.
2. Rake the soil to a fine tilth and sow in rows 25–30 cm apart, about 1 cm deep.
3. Keep the soil moist until the seedlings appear; this usually takes two to three weeks.
4. Thin to 20–30 cm between plants so they grow sturdy and well branched.
5. In March and April, sow a new row every three to four weeks for a longer harvest.
6. Do not feed: poor to ordinary soil gives sturdy stems.

Care

Water

Little needed after germination; water only in long dry spells.

Feeding

Not needed. Too much nitrogen makes the stems floppy.

Weeding

Keep young seedlings free of weeds; they grow slowly at first.

Support

In a windy spot, put up a net or a few twigs between the plants.

Harvesting

Cut the stems in the morning, when the bracts are a good yellow-green, and put them straight into water.

Tip: Sow an extra row in September: the plants overwinter and give earlier, sturdier stems for bouquets the following year.

Thorow-wax: when to prune it?

When: Thorow-wax is not pruned. Regular cutting for the vase makes room for new side shoots.

How:

• Cut long stems for the vase just above a side shoot.
• Strip the lower leaves from cut stems and put them straight into a bucket of water.
• At the end of summer, let a few plants set seed if you want it to self-sow.
• Pull up the dead plants in autumn.

Pruning calendar and basic rules

Propagation

Spring sowing

Sow in situ in March–April, about 1 cm deep, and thin to 20–30 cm.

Autumn sowing

Sow in situ in September. The young plants overwinter and flower earlier and more strongly the following year.

Self-sowing

Let a few plants ripen; on bare soil, seedlings will come up the following year.

Thorow-wax: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Autumn sowings overwinter as small plants and tolerate frost down to about −10 °C.
• In heavy, wet soil they can rot over winter: sow in a well-drained spot.
• In hard frost without snow cover, a layer of fleece protects the young plants.
• Spring sowings die after flowering and setting seed; clear them in autumn.

Diseases and pests

• Slugs: They eat young seedlings. Pick them off in the evening and keep an eye on young sowings.
• Flopping stems: Soil too rich or sown too densely. Thin well, do not feed and put up a net.
• Failed transplanting: Transplanted seedlings stay small or die because the taproot is damaged. Sow in situ.
• Aphids: Sometimes on the stem tips. Spray off with water; natural predators do the rest.

Through the year

• March: Sow in situ, about 1 cm deep.
• April: Sow another row. Thin to 20–30 cm.
• May: Weed and thin. Put up a net if needed.
• June: Flowering begins. Cut stems for bouquets.
• July: Full flower. Harvest; water only in long dry spells.
• August: Last flowers. Let a few plants set seed.
• September: Sow in situ for earlier flowering next year.
• October: Pull up dead plants. Thin autumn sowings.
• December: Cover young plants with fleece in hard frost.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The name thorow-wax means roughly ‘through-grow’: the stem seems to grow right through the leaf.
• Its seed used to travel with seed grain, which made it a common cornfield weed. Better seed cleaning has caused a sharp decline in the wild.
• Thorow-wax belongs to the same family as parsley, carrot and fennel.