Geraniums come in two varieties: “true” and “common. " True geraniums are perennials, so pruning them is a good investment. Common geraniums are annuals, and they also do well with pruning, but since they won’t last more than a season, it’s not absolutely necessary to prune them.
If you live in a temperate climate where the winters don’t get so cold that the ground freezes, you can overwinter your geraniums outside. In colder areas, where the ground freezes hard, you’ll want to dig up your geraniums and keep them in pots indoors for the winter.
If you overwintered your geraniums outside, prune in late March or early April, when the weather begins to warm up. If you overwintered your geraniums inside, wait until the ground has thawed. You can gradually get them used to outdoor weather by putting them outside during sunny, warm days and bringing them back in at night. When the last frost has passed, you can either transplant them to the ground or keep them outside in pots.
Pruning actually spurs new growth of stems and flowers, so trimming back a particular place won’t necessarily leave a hole. If a large part of the plant is dead, you’ll need to do some drastic trimming. The plant should survive as long as the central stalk is still green. However, it might take a few weeks before new leaves and flowers emerge.
Grasp the flower stem just behind the dead blossom with your thumb and forefinger. Pinch the stem and sever it with your thumbnail, then discard the dead flower. Alternatively, you may want to wait until a whole flower cluster is spent, then remove the whole cluster further down the stem down at the next leafy area.
Don’t bother trying to save foliage that seems on the verge of being dead, even if it’s not quite there yet. It’s better to trim it back and let the plant produce strong, new stems.
If you don’t want to make such a drastic cut, follow the flower stem back to 1⁄4 inch (0. 6 cm) above the top of a node, which is a ring around the stem on a geranium. The new growth will sprout from the node.
At the end of the growing season, trim back at least 1/3 of the plant in this way to prepare it for winter dormancy.
Long cuttings can be trimmed into more than one piece. Just make sure each one is trimmed to 1⁄4 inch (0. 6 cm) below a node. Cuttings from flowering branches usually will not root, because they don’t have the correct hormones in them to create roots. The cuttings need to be from growing stems, not from flowering ones.
If the cutting doesn’t have a leaf, you can still plant it. If the cutting has one large, healthy leaf, use a scissors to make a slit in the leaf, leaving both halves attached. A cutting can’t support the surface area of a large leaf.
