Bidens: a trailing balcony plant that flowers until the frosts

A yellow trailing plant for window boxes and hanging baskets. How to plant, water and feed bidens, when to cut it back and what to combine it with so that it flowers from May until the frosts.

In brief: Bidens (Bidens ferulifolia) is a trailing balcony flower with small yellow blooms that flowers from May until the frosts. It wants full sun, a free-draining substrate and regular feeding. It tolerates drought better than petunias but not frost, so it is grown as an annual.

Planting outdoors	after the last frosts, roughly from mid May
Position	full sun, at least 6 hours a day
Length of shoots	trails 30–60 cm, in the ground spreads over a metre wide
Number per window box	2–3 plants per 50–60 cm, in a mix 1 at each end
Frost hardiness	to roughly −5 °C, does not overwinter outdoors in the Czech Republic
Feeding	from June once a week with a liquid fertiliser for flowering plants

In recent years bidens has become one of the most rewarding balcony plants. In spring you see it in every garden centre as a golden cushion in hanging baskets, in summer it spills over the edges of window boxes and, unlike Surfinia petunias, it does not need its spent flowers picked off every day. The dry flowers drop off by themselves.

In this article you will find how to plant it in a window box, how many plants to buy, how to feed it so that it does not stop flowering in August and what to combine it with. The question of whether it makes sense to overwinter it is not left aside either.

Bidens, not forsythia: what bidens is

The genus Bidens is known in English as beggarticks or bur-marigold. On balconies we mainly grow Bidens ferulifolia, originally from Mexico and the south of the USA, and its hybrids. Online it is sometimes mislabelled "golden bell", but that is really a common name of forsythia, a spring-flowering shrub. When searching for young plants, use the name bidens.

The plant has finely divided leaves and flowers 3–4 cm across. Most often they are deep yellow, but breeders also offer orange, cream, pink and two-coloured varieties. In its homeland it is a short-lived perennial; here frost reliably kills it, so it is grown as an annual. Bees and bumblebees visit the flowers.

Young plants or seed?

Most modern coloured varieties are propagated by cuttings and sold only as ready-grown young plants. In spring you can buy them at a garden centre from April. If you want plants more cheaply and do not mind the classic yellow, there are also varieties grown from seed.

Sowing in February to March in seed compost; just press the seeds in and cover lightly.
Germination at 18–22 °C usually within 2 weeks.
Pricking out into separate cups as soon as the seedlings have their first true leaves.
Pinching out the tip at a height of around 10 cm so that the plants branch.

General advice on early spring sowing on a windowsill can be found in the article what to sow in February.

How to plant a window box or hanging basket

Plant outdoors after the last frosts. In a cold May wait; at night temperatures below 5 °C bidens stops growing and the leaves turn purple.
Choose a container with drainage holes. For bidens a window box of 50–60 cm, a hanging basket at least 25 cm in diameter or a bowl on a wall is suitable. A self-watering window box saves a lot of work in July.
Use a good-quality substrate for balcony flowers. If it is heavy and holds water, mix in perlite.
For a 50–60 cm window box 2–3 plants are enough if on their own; in a mix with other flowers, one at each end. Bidens grows fast and within a month fills the space that looks empty at planting.
Plant the young plants to the same depth as they were in the pot, water and protect them from fierce midday sun for the first week.

Which window boxes and pots suit a balcony and why drainage matters is discussed in the article how to choose the right flower pot.

Water and nutrients: so that it flowers in August too

Bidens tolerates brief drying out better than petunias or Surfinias. That does not mean watering once a week is enough, however. In full sun on a south-facing balcony a window box drinks twice a day in the heat. Water as soon as the substrate is dry on the surface and do not leave water standing long in the saucer.

The most common reason why bidens stops flowering in midsummer is hunger. In six weeks it exhausts the nutrients in the substrate and then only grows longer. From June add a liquid fertiliser for flowering balcony plants to the water once a week, at the dose on the label. A fertiliser with a high nitrogen share promotes leaves, not flowers.

Period	Watering	Feeding	Treatment
May	moderately, depending on weather	no, the substrate has nutrients	pinch out the tips
June – July	daily, in heat even 2×	1× a week	nothing, it flowers by itself
end of July	daily	1× a week	cut back by a third if it thins
August – October	depending on weather	1× a week until September	remove dry shoots

Cutting back in midsummer

If at the end of July the plant is long, sparse and flowers only at the ends of the shoots, cut it back with scissors by roughly a third. Feed and water. In two to three weeks it sprouts from the leaf axils and by autumn forms a new dense cushion. Regular deadheading is not needed with bidens.

What to combine bidens with

In combinations bidens is the so-called trailer, a plant that spills over the edge. In the middle of the window box suit upright species with the same needs for sun and water.

Blue and violet: verbena, lobelia, mealy sage. Yellow and blue is the classic contrast.
Orange and red: geraniums, marigolds, creeping zinnia (Sanvitalia). They look warm and rich.
White: white petunias or marguerite daisies, if you want to calm the combination down.

Bidens does not belong in shade; there replace it with begonias or busy Lizzies. You can find other plants for sunny containers and their combinations in the articles balcony plants that flower until autumn and growing on a balcony.

Does it make sense to overwinter bidens?

Usually not. After the season the plants are often exhausted, and new young plants in spring work out cheaper than the space and work of overwintering. If you have a favourite variety, try taking cuttings 8–10 cm long in August, root them in a moist substrate and overwinter the young plants on a bright windowsill at 10–15 °C. In spring you take further cuttings from them.

Troubles you may meet

Lower leaves turn yellow – most often hunger or overwatering. Check the drainage from the container and start feeding.
Few flowers – shade or lack of nutrients.
Tiny pale dots on the leaves and fine webbing – spider mites in hot, dry weather. Misting the leaves and prompt action help.
Aphids on the tips – usually in spring; with a light infestation it is enough to wash them off with a jet of water.

Bidens is not listed in the ASPCA database of poisonous plants. Even so, place containers with flowers so that small children and animals do not nibble them, and store fertilisers out of their reach.

Frequently asked questions

When should I plant bidens outdoors?

After the last frosts, usually from mid May. Bidens does not tolerate frost and stops growing in the cold, so earlier planting gains nothing.

How many bidens plants should I put in a window box?

For a 50–60 cm window box two to three plants if you plant them on their own. In a mix with other flowers one at each end is enough, as bidens spreads quickly.

Does bidens tolerate partial shade?

It does, but flowers less and the shoots thin out. For rich flowering it needs at least six hours of direct sun a day.

Why did my bidens stop flowering?

Most often it is hungry, because it exhausts the nutrients in the substrate by the beginning of summer. Start feeding once a week, cut long shoots back by a third and in two to three weeks it sets flowers again.

Is bidens a perennial?

In its homeland it is a short-lived perennial; in our climate it does not overwinter outdoors, as it tolerates only light frosts. It is therefore grown as an annual, or cuttings are kept over winter.

Sources

Updated: 27 September 2026

Author: Jana Vránová, the editorial name of the Pěstík.cz team. She writes about the garden, herbs and essential oils. We take safety and dosage information from specialist literature and official sources, which we cite in every article.