Martha Washington geraniums have large clusters of flowers in vivid colors like purple, red and orange and some varieties have white blooms. They're not heat tolerant, so they don't bloom well in hot climates unless they're kept in partial shade. Because of this, they're often grown indoors as houseplants. Outdoors, they can be planted in the garden or as container plants. Care instructions are the same as for other geraniums.
Plant geraniums in full sun unless you live in an area where summer temperatures frequently rise above 90 degrees F. Plant geraniums in partial sun in areas with hot summers.
Add compost to the soil to give the geraniums a rich growing medium. If you are planting in containers, use commercially available potting soil rather than garden soil. Plant geraniums in the garden or container at the same height as they were in the pot you purchased them in.
Water Martha Washington geraniums when the soil is dry. Soak the flower bed or container soil and then don't water again until the soil is dry 2 inches below the surface. Don't let container plants sit in a puddle of water. Make sure the plant has good drainage.
Fertilize geraniums at least once a month. Every two weeks is ideal. Use 20-20-20 or 15-30-15 fertilizer and follow the package directions.
Pinch off dead leaves and use garden shears to cut off dead flowers. Don't drop the dead foliage on the ground near the geranium as it may be diseased.