How to Grow a Johnson's Blue Geranium Plant

Johnson's Blue geranium blooms from spring through fall.

Johnson's Blue is a hardy and low-maintenance geranium that produces periwinkle-blue flowers during several blooming periods from spring through early autumn. Johnson's Blue geraniums can grow up to 18 inches tall and form large clumps that spread 18 to 24 inches. This perennial is easy to grow outdoors in U.S. Department of Agriculture hardiness zones 5 through 9. If you live in colder climates, you can plant Johnson's Blue in a pot and bring it indoors during extreme cold spells.

Things You'll Need

• Peat moss and perlite
• Pruning shears
• Sharp shovel

Instructions

1. Plant your Johnson's Blue geranium in partial shade, in well-drained soil. Amend the soil with peat moss and perlite to improve drainage if necessary.

2. Space your Johnson's Blue geraniums about 12 inches apart. Soak the soil with water after planting. Give them a single deep watering every week during the growing season.

3. Trim the geraniums back 25 to 50 percent right after the early-season blooms have faded. This trimming will encourage a second bloom.

4. Trim back any raggedy looking foliage in late summer. Pick off any remaining leaves from the geraniums in the fall, when the foliage wilts.

5. Divide your Johnson's Blue geraniums every third or fourth year in the fall. Slice the clump in half with a sharp shovel. Transplant the sections.

Tips & Warnings

• If you live in USDA zones 1 through 4, plant your Johnson's Blue geraniums in pots with drainage holes. Plant them in a humus-rich potting soil mixed with peat moss or perlite. Bring the pots inside when the weather turns cold.

• If you want to plant Johnson's Blue geraniums in the autumn, do so at least six to eight weeks before the first hard frost is expected. This will give the geraniums time to root and decrease the risk of frost heaving the plants out of the ground.

• Never allow your Johnson's Blue geranium to sit in waterlogged soil. These plants are especially susceptible to root rot.

References

• Easy to Grow Bulbs: Geranium Johnson's Blue

Resources

• Perennial Resource: Geranium "Johnson's Blue"