Anyone who describes the liver balm from the daisy family as a filler is doing this versatile and persistently flowering plant an injustice, because it is a true all-rounder. Depending on the variety, it grows between 10 cm and 70 cm in height, so that it looks just as good in the perennial border as it does as a border, in a flower box, in a bucket or as a grave ornament. Its popular name, blue cap, does not do the herbaceous plant justice either, because it also comes with white, violet, pink, or purple flowers. Given the right care, liver balm with the botanical name Ageratum houstonianum blooms non-stop from May to October.


Liver balsam is often found in well-kept hobby gardens, because the lush flowers last throughout the summer if the following recommendations are observed:

  • A sunny to partially shaded location is ideal.
  • Liver Balm loves it warm and airy.
  • Planting time is after the ice saints, in mid-May.
  • With at least 5 hours of sun a day, it develops magnificently.
  • Fresh and nutritious substrate is welcome.
  • The ideal pH is between 5.5 and 6.6.
  • Water regularly and avoid drought stress.
  • The Ageratum houstonianum does not like waterlogging at all.
  • A dose of liquid fertilizer is given every 2 to 4 weeks.
  • Cleaning faded plant parts immediately promotes flowering.
  • Pull weeds every few days.

Despite all the natural beauty of Ageratum houstonianum, gardeners should refrain from planting when children or pets are nearby, as all parts of the plant are poisonous.


Liver balsam is usually cultivated outdoors as an annual ornamental plant, because the plant does not tolerate frosty temperatures. In its native South America, Ageratum houstonianum is known as a perennial plant. The chances of surviving the winter inside the house, in the heated conservatory or greenhouse are therefore good in a tub or flower box:

  • Temperature must not fall below 5° Celsius.
  • Even in winter, the plant needs a lot of light.
  • It is watered less and not fertilized.

Since overwintering liver balm is quite time-consuming compared to sowing again in spring, most gardeners do without it. However, in this case they miss the possibility of propagation by cuttings in spring.


If you don’t want to buy ready-grown liver balm in spring, you can start sowing indoors or in the greenhouse from February/March. The seeds are distributed in a seed tray filled with nutrient-poor seed substrate mixed with some sand to improve permeability. Since liver balm germinates with light, the seeds are pressed into the ground, but not completely covered. Everything is then slightly moistened with water from a spray bottle . The seed tray is then covered with a pane of glass or cling film and placed in a bright, warm place. At a constant temperature of 20° to 21° Celsius, it takes about 10 to 14 days to germinate.

The strongest seedlings are pricked out after 4 weeks in pots with a diameter of 8 or 9 cm. 3 seedlings are placed in a pot. Gardeners who have cuttings available because they overwintered their liver balm plant 3 pieces in a 10 cm pot. The substrate should continue to be low in nutrients, because this encourages the roots of the seedlings or cuttings to search for nutrients more intensively, so that a strong root ball forms.

In the course of the culture, it is important to ensure that the young plants are permanently slightly damp, but that no waterlogging can form. Experienced hobby gardeners therefore make sure that the growing pots have small holes or slits so that excess water can drain off. The average temperature during this period should not be below 16° Celsius. If there is a risk that the site could come under direct sunlight, appropriate shading is provided. The adult liver balm is a real sun worshiper; however, at this early stage of culture the tender plantlets would suffer sunburn.


After the ice saints, i.e. from mid-May, the Ageratum houstonianum can go outside. A planting hole is dug in the bed at the selected location, which is about twice as large as the root ball. If the potting soil is not airy enough, it is loosened up and mixed with some sand. The addition of some garden compost and some horn shavings ensures a sufficient supply of nutrients right from the start . In this case, however, the first liquid fertilizer is administered after 4 to 6 weeks at the earliest in order to avoid over-fertilization. The planting distance depends on the selected variety. As a rule of thumb, planting in groups of five will result in more compact growth.

If liver balm is intended to decorate terraces and balconies in flower boxes or tubs, conventional potting soil is perfectly adequate as a substrate. As with the growing pots, it is important that there are sufficient drainage options for irrigation water. Ideally, a drainage made of fine gravel or perlite should be laid over it to ensure that no waterlogging can occur.

diseases and pests

Although all parts of the liver balm are poisonous, some pests still attack the plants. In this way, aphids, small nematodes that are 1 mm long, can be spread with the irrigation water. If there are glassy spots on the leaves that later turn brown, they should be removed immediately. You should avoid spraying the plant afterwards or boil the water beforehand. If the infestation is already well advanced, the entire plant is discarded to prevent it from spreading to other plants. Another danger comes from aphids and whiteflies. Since these pests are widespread in the garden, there are now numerous biological means available to put an end to them:

  • shower vigorously
  • lacewing larvae
  • parasitic wasps
  • ladybug
  • nematodes
  • nettle brew

In addition, a mixture of 1 liter of water, 1 tablespoon of pure soap and 1 tablespoon of spirit has proven itself, with which the affected plants are sprayed on several days in a row.

If the plants are too wet, there is a risk of root rot. This is a fungal disease caused by waterlogging. The plants no longer grow, let their leaves hang limp and also do not develop new flowers. To prevent root rot, liver balm should never be planted in soil that is too heavy. A permeable substrate on a drainage is therefore essential in pots and flower boxes.

In the event that speckles appear on the leaves of the liver balm that are not due to a pest infestation or a disease, the cause is usually unfavorable lighting conditions or temperatures that are too cool.

Gardeners who leave their Ageratum houstonianum at home over the winter will quickly encounter spider mites . These only become really active when the heating air is dry and do not spare the liver balm either. They are only 0.5 mm in size, have eight legs and a light yellow body. They pierce individual plant cells and suck them out, causing them to die off after a while. Liver balm isn’t one of her favorite foods; nevertheless, this type of plant can also be infested by spider mites – usually in the absence of alternative offers. In this case, regular spraying with water can help. However, so that the door is not opened to the leaflets, it is advisable to boil the water beforehand.

Popular Varieties

Liver balm is now available in numerous attractive varieties, of which we present some of the most popular breeds below:

Blue Danube

  • light blue flowers
  • compact growth habit
  • Height 15 cm to 20 cm

Blue Horizon

  • medium blue flower color
  • Growth height up to 70 cm
  • Flowering period June to September

cutting miracle

  • bright blue flowers
  • ideal as a cut flower
  • Growth height up to 70 cm
  • particularly strong stems

white cut

  • beautiful, pure white flowers
  • cut compatible
  • Growth height up to 70 cm
  • Flowering period June to September

Low Purple

  • purple flowers
  • particularly early liver balm variety
  • Flowering time April to September
  • Growth height up to 45 cm

Alto Delft

  • flower color purple
  • Growth height up to 35 cm
  • well suited for flower boxes
  • Flowering time May to September


  • rare variety
  • shines like the starry sky
  • two-tone in white and blue
  • Growth height 15 cm to 20 cm
  • well suited for boxes and tubs


  • Flowers shine in light blue
  • Growth height 15 cm to 20 cm
  • beautiful as a border and in a box
  • Flowering period June to October


  • Flower color ultramarine
  • Growth height up to 20 cm
  • compact growth habit
  • Flowering time May to September

Blue Eyes

  • deep blue flowers
  • compact growth up to 20 cm
  • has performed well in the field
  • Flowering time May to October

Old Grey

  • grey-blue flowers
  • Growth height up to 50 cm
  • absolute rarity
  • Flowering period June to September


  • bright white flowers
  • stocky shape
  • extremely tolerant of cuts
  • grows up to 30 cm high
  • Flowering time May to October

Blue basket

  • deep blue flowers
  • grows up to 20 cm high
  • Flowering time May to September
  • creates a beautiful carpet of flowers

All liver balm varieties not only result in dense carpets of flowers and thrive in flower boxes and tubs, they also complement each other wonderfully with delicately colored roses or bright yellow marigolds. The large-growing varieties serve as a creative design element when planted in the background of small-growing flowering perennials. Liver Balsam is so multifaceted that gardeners can let their imaginations run wild and reinvent their plant every year.

Liver Balm comes from the tropical climes of South America and Mexico; also feels at home in the local regions in spring and summer. The botanical name Ageratum houstonianum means ‘forever young’, which is by no means an exaggeration. With the right care, liver balm blooms tirelessly from May to October. If the location, substrate, moisture and nutrients are right, not only wonderful carpets of flowers and bed borders are created, but also decorative flower boxes and tubs. Overwintering is a bit tedious, which is why the majority of hobby gardeners do without it, because sowing in spring is not a feat even for newcomers to gardening. However, the name liver balm should not be misunderstood as a name for a healing plant, because exactly the opposite is the case:

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