Buenos Aires verbena (Verbena bonariensis) is an airy and generous perennial, valued for its long, airy summer flowering, its country-style look and its ability to attract pollinating insects. Often grown as an annual, it's possible to harvest its seeds in autumn then sow them the following spring, so you can enjoy its qualities year after year. This simple, economical method makes it easy to propagate the plant, while preserving its natural charm in the garden.

Discover our tips to harvest and sow Buenos Aires verbena.

Buenos Aires verbena

When and how to harvest seeds of Buenos Aires verbena?

Harvesting generally takes place in late summer or early autumn, when flower stems have faded and seeds have had time to ripen.

  1. Watch the inflorescences: seeds form at the base of faded flowers as small dry, brownish fruits that detach easily when mature.
  2. Choose a dry day to harvest the seeds, ideally late morning, to avoid moisture that could affect their storage.
  3. Collect the seeds by hand: pinch the flower heads between your fingers and rub them gently to release the seeds.
    Tip: a fine sieve or a colander can help separate them from plant debris.
  4. Dry the seeds for a few days away from light in a well-ventilated place, ideally spread in an open container on absorbent paper or a clean cloth.
  5. Store them in a paper envelope, a kraft bag or an airtight box, noting the date and the plant name (and possibly the variety).
Buenos Aires verbena flowers

When and how to sow Buenos Aires verbena seeds?

Sowing Buenos Aires verbena is easy to achieve, provided a few conditions are met. It is best done between February and April, under cover or indoors, before transplanting outdoors after frosts.

Necessary equipment

Steps for sowing

  1. Fill your buckets or a tray with the special seed compost, optionally mixed with some sand to prevent excess moisture.
  2. Sow the verbena seeds on the surface, as they need light to germinate (they are photosensitive). Do not bury them, but press them lightly against the substrate to ensure good contact.
  3. Spray water to moisten the substrate without flooding it.
  4. Cover the buckets with a transparent lid or film to create a greenhouse effect.
  5. Place everything in light and at a mild temperature (18 to 21 °C) to encourage germination. Seeds generally germinate between 10 and 20 days after sowing.
  6. Ventilate regularly to avoid damping-off and remove the cover as soon as the first leaves appear.
  7. Transplant outdoors when young plants have 4 to 5 leaves, after the last frosts. Choose a sunny spot, sheltered from strong winds and in well-drained soil. Beware slugs and snails, which favour these young shoots.
young seedlings

Care of young Buenos Aires verbena plants

Watering
Water sparingly and in case of no rain during the first weeks. Once well-rooted, Buenos Aires verbena becomes very undemanding and tolerates summer drought without concern.

Pinching (facultative)
Optionally pinch the tips of young plants to encourage denser branching, although the plant naturally adopts a slender, architectural habit.

Propagation
At the end of the season, leave a few stems to go to seed if you want to harvest again or encourage a natural spontaneous sowing.

Did you know?
In mild climates, Buenos Aires verbena can even behave as a semi-evergreen perennial, while elsewhere it is grown as a generous annual, to be sown again each year.