How to help struggling plants thrive in your summer garden

Clematis, like these compact Daiyuclematis, begin to take center stage in western Washington gardens when the spring bulbs begin to fade.

Clematis, like these compact Daiyuclematis, begin to take center stage in western Washington gardens when the spring bulbs begin to fade.

Monrovia Nurseries

Early June is all about roses and clematis as summer blooms fill in where tulips and late spring bulbs wilt.

This is also the week to consider bringing some houseplants outside for a summer vacation. Most houseplants prefer shade to full sun when brought onto the porch or patio, and just like humans, plants need to build up a “tan” before they can handle direct sun without burning.

If you haven’t yet fertilized your houseplants, perennials or annuals, now is the time to apply plant fertilizer. The days are much longer, so plant growth is accelerated, and just like humans, the faster a plant grows, the more nutrients it needs.

Q. I so admired the flowering maple or Abutilon ‘Red Tiger’ at the Northwest Flower and Garden Show a few years ago and bought a small plant. Never before has a flowering plant attracted more attention from visitors. The flowers look like dangling lanterns with red and orange stripes. I was able to overwinter my plant for two years just by placing it near the house. It had grown to be 5 feet tall! Now my question: This year the leaves are still not budding and I’m afraid my Abutilon is dead. What I have done wrong? — GF, Puyallup

A. Don’t blame yourself – point your finger at the weather. Abutilon is a warm climate plant that could survive a mild winter, but really didn’t like the weather pattern last spring. We had a hot spell in April that woke this delicate plant from hibernation, then cold set in again and the shock was just too great. Or was it?

It’s possible that just like clematis vines that are disappearing and presumed dead, your flowering maple could be a Lazarus, sending up a new shoot or new leaves near the base of the old plant. I suggest you wait until July 4th to declare a leafless plant dead.

Warning: You may be to blame for this death if you prune some tall and leafless branches of your abutilon during a spring clean. Many tender plants do not die from the weather, but from cutting too early. (Hardy fuchsias and sage also hate spring pruning.) Pruning always stimulates growth, and waking up a dormant plant with a pruning can be death.

The good news is that local nurseries now offer many varieties of flowering maple or abutilon, and these spectacular patio plants are healthy hummingbird eaters too.

Q. My lavender plants are a few years old. They have new top growth and are flowering now, but the base of the lavender plants is bare or ugly with brown leaves. Can I cut them all back and start over? — LL Enumclaw

A. Just wait. When your lavender plants are done with their first bloom, you can prune them back heavily, but don’t go too far into the old, bare, woody stems or the shock could kill them.

The truth is that lavender plants are a perennial that hate cold, wet weather, and in western Washington you should only expect about three or four years of life from the typical lavender plant — except if you live in the dry area around Sequim.

However, lavender plants are easy to start with cuttings. So when you prune the tops of your plants, you can tuck the cut stems (without flowering spikes) into the ground, leaving about 2 inches of the stem underground. Remove all of the lowest leaves from the bottom half of the stem cuttings just before sticking them in moist soil. New roots form at the bumps or nodes where leaves have grown. My theory on the process of making new plants by poking stems into soil at random is to take many cuttings and assume that one in 10 will “take” or root. You’ll have plenty of plant material for cuttings after you prune a plant, so there’s nothing to lose by experimenting with stem cuttings, and you could win free plants you create yourself.

Q. Is it too late to prune my hydrangea bush? It’s gotten so big it’s blocking a window. — B, email

A. Do not prune your hydrangea bush now or you will cut off any unopened blooms.

Shrubs such as rhododendrons and hydrangeas that grow too large for their space are best transplanted where they can grow to their true size. Don’t try to fight Mother Nature.

Some modern hydrangeas such as the ‘Endless Summer’ cultivars flower from new wood, so if you cut branches in bud or bloom, new growth can appear and flower in the same summer. The old fashioned or traditional hydrangeas only bloom on 2 year old wood, so early summer pruning will remove future blooms.

Marianne Binetti holds a degree in horticulture from Washington State University and is the author of several books. Reach them at binettigarden.com.

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