Ciscoe Morris, a Seattle Times' garden writer, offers tips on growing calla lilies; keeping birch trees healthy and free of the bronze birch borer; and boosting your broccoli yield.

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The calla lilies (Zantedeschia) featuring colorful flowers are a must for any garden. The sturdy, spotted white leaves add lovely charm even when they’re out of flower, but it’s the brilliant, vase-shaped spathe blooms that give these plants an irresistible tropical flair. Look for incredible hybrids potted up at your local nursery.

“Flame” is one of the hardiest with blossoms that emerge yellow then turn fiery orangish-red. “Mango” features unique variegated orange and red flowers. The spathes on “Edge of Night” are such a rich, dark purple, they may appear black at times.

These hybrids don’t always survive harsh winters, so it’s best to dig the bulbs in fall or grow them in pots in order to overwinter them in an unheated garage.

Unlike the callas with the white flowers which prefer semi-shade, these colorful ones require full sun in order to bloom well. They do best in well-drained soil, and appreciate regular watering and feeding, especially if you’re growing them in a pot.

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If you decide to take your chances (as I usually do) and leave them outside during winter, the bulbs usually survive if they’re planted where there is exceptional drainage and you mulch heavily in the fall with a cover of evergreen fern fronds.

You’ll know you were successful when leaves begin to emerge in mid-May, and the magnificent flower display begins again in early to mid-July.

Beware the

bronze birch borer

The bronze birch borer has been a longtime pest of birch trees in Eastern Washington; unfortunately, it’s becoming a serious problem on the west side of the mountains as well. Symptoms begin with yellowing stunted foliage in the upper canopy, followed by branch dieback. Severe infestations usually result in the death of the tree.

The adult is a narrow bronze beetle that can grow to a half-inch long, but the damage is caused by the larvae feeding inside the tree. All birch trees are susceptible to this pest, but it’s the popular white barked ones, European weeping birch (Betula pendula) and the Himalayan birch (B. jacquemontii) that are often attacked.

If you have birch trees, try to keep them healthy. Vigorous trees are less attractive to the beetles and are usually able to fend off attacks, while weak, stressed trees release chemicals that attract the beetle.

To stay healthy, birch trees require well-drained soil and protection from hot afternoon sun. Mulch over the root zone and water deeply once per week in hot weather.

If your birch tree becomes infested, it could mean that the tree is not happy in its environment and perhaps it’s time to visit the nursery to pick out a new type of tree.

Keep your broccoli producing

Broccoli is an easy vegetable to grow, and it’s delicious and incredibly good for you. The first trick to keep them producing well is to make sure they aren’t too crowded.

Remove weeds regularly, and even if you have to remove a plant or two, thin to allow at least 14 inches between individual plants.

Broccoli has a big appetite so feed every four weeks by working in organic vegetable food around the plants and water as often as needed to keep the soil evenly moist.

Harvesting the main head is tricky. You want to wait until it sizes up, but for the best flavor you need to pick it while it is still green and has not begun to turn yellow. Cut the head off at a 45-degree angle at the base of the flower stalk. That will encourage side shoots to grow from below the cut.

Side shoots won’t be as big as the main head, but they’ll be equally delicious.

Ciscoe Morris:; “Gardening with Ciscoe” airs at 10 a.m. Saturdays on KING 5.

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