Yard and Garden: Overwintering Geraniums for Spring Replanting


September 28, 2016, 5:01 pm | Richard Jauron, Greg Wallace

AMES, Iowa – Geraniums are beautiful plants which add color and vibrant detail to any landscape. However, they are ill-equipped to survive harsh winter conditions. There is a solution: Geraniums can be taken indoors and overwintered, then replanted in the spring.

ISU Extension and Outreach horticulturists can help answer your questions about overwintering geraniums and how to preserve them during winter conditions. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or hortline@iastate.edu.

How can I overwinter geraniums indoors?

Geraniums can be overwintered indoors by taking cuttings, potting up individual plants or storing bare-root plants in a cool, dry location. Remove plants from the garden (or take cuttings) prior to the first fall frost.

Geraniums

How do you take geranium cuttings?

Using a sharp knife, take three-to-four-inch stem cuttings from the terminal ends of the shoots.  Pinch off the lower leaves, then dip the base of each cutting in a rooting hormone. Stick the cuttings into a rooting medium of vermiculite or a mixture of perlite and sphagnum peat moss.  Pots and flats with drainage holes in the bottom are suitable rooting containers. Insert the cuttings into the medium just far enough to be self-supporting. After all the cuttings are inserted, water the rooting medium.

Allow the medium to drain for a few minutes, then place a clear plastic bag or dome over the cuttings to prevent the plant foliage from wilting. Finally, place the cuttings in bright light, but not direct sunlight. The cuttings should root in six to eight weeks. When the cuttings have good root systems, remove them from the rooting medium and plant each rooted cutting in its own pot.  Place the potted plants in a sunny window or under artificial lighting until spring.

How do you overwinter geraniums as potted plants?

Carefully dig up each plant and place in a large pot. Water each plant thoroughly, then place the geraniums in a sunny window or under artificial lighting. Geraniums prefer cool indoor temperatures. Daytime temperatures of 60 to 65 degrees Fahrenheit and slightly cooler night temperatures are ideal. Water plants about every two weeks. Geraniums are likely to become tall and lanky by late winter. In March, prune back the plants. Cut the geraniums back by one-half to two-thirds. The geraniums will begin to grow again within a few days and should develop into attractive specimens by May. 

How do you overwinter geraniums as bare-root plants?

Carefully dig up the geraniums before the first fall frost. Shake the soil from the plant’s roots.  Then place one or two plants in a large paper sack and store in a cool (45 to 50 degree Fahrenheit), dry location. An unheated bedroom or indoor porch might be a suitable location.  An alternate (somewhat messier) method is to hang the plants upside down in a cool, dry location. The foliage and the shoot tips will eventually die.

In March, prune or cut back each plant. Remove all shriveled, dead material. Prune back to firm, green, live stem tissue. After pruning, pot up the plants and water thoroughly. Place the potted geraniums in a sunny window or under artificial lighting. Geraniums that are pruned and potted in March should develop into attractive plants that can be planted outdoors in May.  

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