When to plant geraniums?
- Botanical name
- Pelargonium
- Family
- Geraniaceae
Geraniums are planted in May. They flower from May to October.
Geraniums are perennial plants. The edible parts are the leaves and flowers.
The pelargonium does not take freezing. It goes outside only once the danger of frost is past, and it comes back indoors before the first autumn frost.
It passes the winter in a bright, airy room, at the brightest window. Watering is sparing, so that the medium dries to the bottom of the pot between two waterings. Moist air and heavy watering together bring on oedema, corky spots on the leaves.
It moves into a fresh pot in spring, before it goes out. Green cuttings are taken from spring to autumn and raised into young plants for the next season.
Geraniums through the year
- planting
- flowering
- repotting
In short
The last frost is not on the same day everywhere, so the recorded weeks are a guide and not a date.
Growing conditions
The leaves are listed as edible and as toxic at once. The toxicity is to cats and dogs, not to people.
Are geraniums toxic to cats and dogs?
Yes. Toxic to cats and dogs, toxic parts: leaves.
Pests and diseases
Listed here is every problem for which the sources name this plant as a host. The problems are not listed in order of how common they are.
- Signs
- Small dark gnats run over the surface of the compost or fly just above it. The larvae, with a shiny black head, live in the compost. At first the plant only loses its healthy look.
- Prevention
- The trouble is nearly always compost that is too wet and rich in peat: let the top layer dry out between waterings. A layer of sand or fine gravel on top of the pot takes the gnats' place for their eggs away.
- What to do
- Products with Bacillus thuringiensis israelensis are watered into the compost and work on the larvae, not on the adult gnats.
- Signs
- Flecks of white waxy wool in the leaf axils, along the leaf sheaths and in other sheltered corners of the plant. Under them sit soft pink bugs and orange eggs. The plant is sticky with honeydew, black sooty mould grows over the leaves, growth stalls and the leaves may drop early. Some species live on the roots and show up only at repotting.
- Prevention
- The females neither fly nor walk far, so you nearly always bring them in with a new plant: check the leaf axils when you buy and keep a new plant apart from the collection for a while. Clear away dead leaves and prunings as they appear, because the eggs are on them. A plant will take a few mealybugs. A badly infested one is often cheaper to throw away than to rescue. In a greenhouse the predators hold them down, the ladybird Cryptolaemus and parasitic wasps, which work in the warm half of the year.
- What to do
- The waxy coat repels the spray, so potassium soap has to reach exactly the leaf axils where the bugs sit, and a single application is rarely enough. Single nests are easiest to take off with a cotton bud.
- Signs
- Scale like bumps stuck to the stem and the underside of the leaves, on the indoor species preferably along the midrib. They do not move and are easy to overlook as part of the plant. The soft scales give off honeydew, so the leaves turn sticky and blacken with sooty mould. In a heavy attack the growth falters.
- Prevention
- As with the mealybugs: the adult females do not fly, so they arrive with a new plant. Check the stems and the veins on the underside of the leaves and keep a new plant apart for a while. A healthy, well kept plant takes the odd scale and action is not always needed. Put a plant that may go outdoors in summer outside, because cooler air and the predators do more than spraying.
- What to do
- An adult scale is protected from the spray under its waxy shield, so scrape it off with a fingernail, a cloth or an old toothbrush while there are few of them. A badly infested house plant is often better thrown away than treated.
- Signs
- Small pale dots show over the upper side of the leaf, with a generally faded look. In a heavy attack the leaf browns or yellows and the plant dies. When it gets worse, a fine web is visible between the leaves.
- Prevention
- Most at risk are the plants that stand in the dry air of a room all year. Mist regularly and raise the air humidity to lessen the trouble. Keep new plants apart from the others for a few weeks.
- What to do
- On sturdy plants wash them off thoroughly with water first. Then potassium soap, which works on contact and has to reach the underside of the leaf.
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Related plants
The plant below is in the same botanical family (Geraniaceae).
Sources about the plant: ASPCA Toxic and Non-Toxic Plants, Clemson Cooperative Extension, GBIF Backbone Taxonomy, NC State Extension Plant Toolbox, Royal Horticultural Society, Wikidata. Checked between 14 and 22 August 2026. The problem descriptions also draw on: EPPO Global Database.