Mugwort Seedlings: Raising Young Plants and Getting Them Going

Where your young plant came from

Most people start with a division or a bought plant rather than seed, and that is the right way round. Mugwort produces enormous quantities of wind-blown seed, so deliberately letting a plant flower in order to collect it puts far more seed into the neighborhood than you would ever use.

Deliberate sowing is only really worth it if you have no access to a division at all. If you do sow, sow into a covered tray indoors and never broadcast seed outdoors, where the germination rate in open ground will surprise you.

If you are sowing seed

The seed is dust fine and needs light to germinate, which makes it easy to lose by burying it. Everything about the technique follows from those two facts.

1. Surface sow only Fill a tray with fine damp seed-starting mix, firm it lightly, and scatter the seed thinly across the surface. Do not cover it with compost. Press it gently into contact with the surface instead.
2. Water from below Stand the tray in shallow water until the surface darkens, then take it out. Watering from above washes the seed into pockets and buries half of it.
3. Warmth and light Cover with a clear lid and keep it around 68F (20C) in bright indirect light. Germination takes one to three weeks and is uneven, so do not give up on a tray after ten days.
4. Ventilate as soon as it germinates Seedlings this small damp off quickly. Prop the lid open once most have appeared and remove it altogether within a few days.

Sow far less than feels sensible. A pinch of seed produces dozens of plants, and surplus seedlings still have to be disposed of responsibly rather than tipped out on the ground.

Transplanting seedlings and the first pot

Move seedlings on once they have two or three true leaves, handling them by a leaf rather than the stem. Grow each on in a three-inch (8 cm) pot of ordinary free-draining compost until roots show at the drainage holes, then go straight into the final container.

That final container should be at least three gallons (12 liters) and should stand on a hard surface, not on soil. A young plant put into its permanent home early makes far better growth than one shuffled through several pot sizes, and standing it correctly from the start avoids a rooted-through pot later.

The first season outdoors

Harden a young plant off over a week or so before it goes out permanently, and give it full sun once it is outside. Water it while it is establishing, then let it take its chances. Mugwort grows on waste ground and a young plant treated too kindly makes soft growth that flops.

Pinch the growing tip once it is a few inches tall to force branching from the base. Pick only lightly in the first season, taking soft shoot tips in spring, and give it a proper hard cut back only from the second year onwards.

Do not let a first-year plant flower. Even a small plant produces viable seed, and the habit of cutting flower stems is much easier to keep if it starts in year one.

Recognizing seedlings you did not want

If a plant near you has flowered, mugwort seedlings will appear the following spring, often some distance away. They come up as small rosettes of deeply lobed leaves with a distinctly white, felted underside, and that silver reverse is the giveaway when the leaf shape is still ambiguous.

Pull them the moment you can identify them, while they still lift with a single thin root. A seedling left through one full season builds a rhizome, and after that it comes back from whatever you leave behind.

Keep a note of where and when volunteers appear. A cluster in the same corner two springs running usually points at a specific parent plant, either yours or a neighboring one, and tells you where the flowering stems are being missed.