By the middle of June you can finally plant all your warm-season crops into the garden. Corn and bean seeds, cucumbers, squash and tomatoes will not have to battle cool nights and cold soil, and they will grow much more quickly than if set out in May. Colorful coleus with fantastic foliage will also perk up this month as the days and nights stay warm.
A few questions from readers:
Q. I bought some coleus plants with huge leaves because I always heard coleus like the shade. My neighbor insists coleus do well in the sun. Does coleus prefer sun or shade? One more question — when my coleus forms a spike of blue flowers do I have to pinch this off the plant? G. Email
A. Coleus are tropical plants that love warm days and do best in light shade or strong filtered light, but there are some new coleus varieties called “sun coleus” that can handle full sun in our climate. In general, the more red you see in a coleus leaf the more sun tolerant it will be.
Pinching off any flower spikes that form on coleus plants will keep them producing colorful leaves rather than putting their energy into seed production. In Western Washington, you should also pinch back the tips of coleus plants several times in the summer to keep them compact and tidy.
New coleus plants are easy to start from cuttings just by placing your pruning bits in a glass of water to enjoy as cut flowers. Keep the glass filled until roots form and you can pot up the cuttings and enjoy new coleus all winter as houseplants.
When it comes to coleus varieties, sometimes the names of the various coleus plants are as colorful as the foliage. Look for “Inky Fingers,” “Stained Glasswork,” “Kong” with huge leaves up to 8 inches across or the dramatic red and yellow variety that can handle full sun named “Big Red Judy.”
Q. I purchased a Martha Washington geranium for the center of a large container garden, and it has stopped blooming. The other plants in the container are marigolds and petunias and they are doing great so I know that I am not giving the plants too much or too little water. This container is in full sun against a sunny wall so I know the plants did not get too cold at night. I planted all the plants a month ago. Why would only the geranium stop blooming? T.Y., Enumclaw
A. The clue to this mystery is the location of your container. A warm and sunny spot is perfect for petunias, marigolds and most geraniums, but Martha or Lady Washington geraniums are more particular about their growing conditions than the other more adaptable geranium varieties. Dry soil or hot afternoons will send Martha into a tizzy. She prefers only morning or early afternoon sun, soil kept moist and a constant supply of weak fertilizer to keep her healthy.
You can always dig out and replace cranky or ungrateful plants from less than successful container garden compositions. The traditional zonal geraniums will thrive in that hot spot and if moved out of the spotlight and into a cooler location your Martha Washington geranium might just settle down and clean up her persnickety reputation.
Q. I am new to the area, but last year I planted canna ‘Tropicanna’ in a large half wine barrel. I was delighted that the huge leaves have sprouted from the same tuber even though the plant looked dead in the winter and I cut the stem all the way to the ground. So will this tropical plant keep coming back year after year? Will I need to dig and divide the bulbs at some point? I should mention that the ornamental grass called Japanese forest grass also came back in the same pot, so I have a wonderful combination of foliage in one pot without replanting anything! P.O., Tacoma
A. Welcome to Western Washington, where our recent mild winter has allowed marginally hardy plants to make an encore appearance. You can grow canna in that same container for three or four years before it should need digging up and dividing, but wait until fall to do the dirty deed.
Cut back the foliage, remove the tuber and separate the knobby roots into three or four smaller tubers. Even cannas planted in the ground survived this past winter if they were growing in well-drained soil. To make sure your potted cannas survive a colder winter in the future, you can move the pot under the eaves or another protected spot out of the rain.
If you plant cannas into the ground, cover the soil with oil cloth or sword fern fronds in the fall after you cut the canna foliage to the ground. In our climate we lose more bulbs to rot from the rainy winters than we do from a deep freeze. Canna tubers can also be dug in the fall and stored in a cold, but not freezing, garage or basement.