Verbena for Window Boxes: Sowing, Growing and Care of Garden Verbena

Growing verbena – loamy-sandy well-drained substrate, sunny position or partial shade, moderate watering and damp conditions

In brief: Garden verbena (Verbena x hybrida) is a popular annual for window boxes and beds that flowers from June until the frosts. Unlike wild-growing common vervain, it is a hybrid bred for abundant and long-lasting flowering, which needs a sunny position, well-drained soil and regular deadheading.

Sowing for seedlings	February–March, warmth 20–22 °C
Planting out	after the last frosts, mid-May
Spacing	20–25 cm
Position	full sun to light partial shade
Flowering	June until the first frosts

The verbena that is commonly sold today as an annual for window boxes and bedding groups is the garden hybrid Verbena x hybrida, different from the wild-growing common vervain of meadows and field margins. Its advantage is abundant, long-lasting flowering in a colourful range from white through pink and purple to red.

In this overview you will find how to sow verbena or buy it as a plant, what its requirements for position are and how to care for it so that it flowers from the beginning of summer until the first frosts.

Garden verbena or common vervain

Garden verbena sold as an annual (Verbena x hybrida) is a cross of several South American species and was bred above all for abundance and length of flowering. Common vervain (Verbena officinalis), by contrast, is a wild-growing perennial herb with tiny flowers, which occurs here on field margins, pastures and along paths and in the Czech Republic is among the endangered species of category C3 – so collecting it in the wild is not recommended. The plant from the e-shop discussed below is precisely the ornamental garden hybrid intended for window boxes, containers and bedding groups, not the wild species from field margins.

Sowing and raising seedlings

Sow verbena seeds, for example Verbena – mix (Verbena x hybrida) or Crossed verbena – mix, from February to March into seed substrate, pressing them in only lightly, because they need light to germinate. The temperature should be around 20–22 °C; germination takes two to three weeks and tends to be uneven. After germination, prick the seedlings out into individual pots as soon as they have their first true leaves, and gradually harden them off before planting out. A step-by-step procedure is also described in the article Verbena: sowing, growing in a window box and in a bed.

Feature	Garden verbena (Verbena x hybrida)	Common vervain (Verbena officinalis)
Plant type	annual, hybrid	wild-growing perennial
Flowers	large, abundant clusters, coloured varieties	tiny, sparse, pinkish
Occurrence	only in cultivation, from seed or plant	field margins, pastures, paths; endangered species in the Czech Republic
Use	ornamental – window box, bed	historically a medicinal herb, now protected

Position, soil and planting

Verbena likes loamy-sandy, well-drained soil and a sunny position; it also tolerates light partial shade, but in denser shade it flowers less abundantly. Plant it out only after the last frosts, usually in mid-May, with a spacing of 20–25 cm between plants depending on how dense a stand you want. Besides beds, verbena also suits window boxes and hanging containers, where its trailing varieties hang prettily over the edge.

Watering, feeding and deadheading

Watering should be moderate to medium – verbena tolerates short-term drought better than permanently waterlogged soil, in which the roots easily rot. During the main flowering season feed roughly once every two weeks with a fertiliser for flowering annuals. Remove spent flower heads regularly; this encourages the formation of new buds and extends flowering until autumn.

Diseases and pests

With waterlogging or insufficient air circulation between plants, powdery mildew may appear on verbena, showing as a whitish coating on the leaves – sufficient spacing at planting and watering at the roots, not on the leaves, help. Aphids appear on verbena rather exceptionally; if they do, rinsing with a jet of water or treatment with a potassium soap-based product is enough. Regular removal of spent and damaged parts also limits the risk of further fungal diseases multiplying on damp plant remains.

Combinations with other annuals

Verbena complements other sun-loving annuals with similar requirements, for example petunias, marigolds or scarlet sage – all tolerate a similar rhythm of watering and feeding, so they can be combined in one window box mix without fear that they would harm one another. Low, bushy varieties of verbena also suit the front of a mixed bed, while taller and trailing types suit the back or edge of a window box, from where they can hang freely over its rim to the ground.

Colour combinations are worth considering in advance – verbena is available in white, pink, purple, blue and red, and because it flowers continuously all summer, it pays to choose shades that will also work well side by side after several months of growing together, not just on the very day of planting.

Overwintering stock plants

Although verbena is usually grown here as an annual, a favourite variety can be tried over winter in autumn as a stock plant in a bright room at a temperature of around 10–15 °C and with limited watering. From a plant overwintered this way it is then possible in spring to take tip cuttings and thus obtain new plants before seeds sown only in the new year manage to germinate and grow sufficiently.

Frequently asked questions

Is garden verbena from a window box the same plant as the medicinal vervain from meadow edges?

No, they are related but different species. Garden verbena (Verbena x hybrida) is an ornamental hybrid for abundant flowering; common vervain is a wild-growing species that is endangered here.

How long does verbena flower?

With regular deadheading and plenty of sun it flowers from June until the first frosts, that is, practically the whole summer and autumn.

Does verbena survive winter outdoors?

No, here it is grown as an annual that does not survive winter outdoors. In spring it is sown or new plants are bought.

Why does verbena not flower, even though it is growing and has a lot of leaves?

The most common cause is lack of sun or over-feeding with nitrogen at the expense of flower formation. A sunnier position and a fertiliser with a higher proportion of phosphorus and potassium help.

Is verbena suitable for hanging window boxes?

Yes, trailing varieties of verbena are a popular choice for window boxes and hanging containers precisely thanks to their long trailing shoots full of flowers.

How often should verbena in a window box be watered in summer, and can it be combined with other annuals?

On hot days watering may be needed even once a day, because the substrate in a window box dries out quickly – water according to how quickly the top layer of substrate dries, not by a fixed schedule. Verbena combines well with other annuals if they have similar requirements for sun and watering, for example with petunia, marigolds or scarlet sage.

Sources

Updated: 10 October 2026