How to help struggling plants thrive as summer blooms replace spring bulbs

The beginning of June is all about roses and clematis, as summer blooms start to fill in where tulips and late spring bulbs are fading.

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

If you have not yet fertilized your houseplants, perennials, or annuals, this is the time to apply plant food. The days are much longer so plant growth is accelerated and just like people, the faster a plant grows, the more it needs nutrients.

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 has a blooming plant gotten 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 moving it close to the house. It had grown to become 5 feet tall! Now my question: This year the leaves are still not popping out and I fear that my abutilon is dead. What did I do wrong? — G.F., Puyallup

A. Don’t blame yourself — point the finger at the weather. Abutilon is a warm-climate plant that might survive a mild winter but really did not like the weather pattern this past spring. We had a warm spell in April that woke this tender plant up from winter dormancy, then coldness set in again and the shock was just too much. Or was it?

It is possible that just like clematis vines that disappear and are presumed dead, your flowering maple could be a Lazarus and send up a new shoot or leaves from near the base of the old plant. I suggest you wait until the Fourth of July to declare a leafless plant dead.

Warning: You can be to blame for this death if during a spring cleanup you pruned down some tall and leafless branches of your abutilon. Many tender plants are killed off not by the weather but by pruning them too early. (Hardy fuchsias and salvias also hate spring pruning.) Pruning always stimulates growth and waking up a dormant plant with a trim can be the death of it.

The good news is that local nurseries are now offering many varieties of Flowering Maple or Abutilon and these spectacular patio plants are also healthy hummingbird feeders.

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

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

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

Lavender plants are easy to start from cuttings, however, so when you prune off the tops of your plants, you can poke the cut stems (sans flowering spikes) into the soil so that about 2 inches of stem is underground. Remove all the lowest leaves from the bottom half of the stem cutting just before poking it into damp soil. New roots will form on the bumps or nodes where leaves were growing. My theory on the process of making new plants by casually poking stems into soil is to make many cuttings and assume 1 out of 10 will “take” or make roots. You will have plenty of plant material for cuttings after you prune any plant, so there is nothing to lose by experimenting with stem cuttings, and you could gain free plants you create yourself.

Q. Is it too late to prune back my hydrangea shrub? It has grown so tall, it is blocking a window. — B., Email

A. Do not prune your hydrangea shrub now or you will be cutting off all the unopened blooms.

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

Some modern hydrangeas such as the “Endless Summer” varieties will flower from new wood so that if you cut branches in bud or flower, new growth may appear and bloom the same summer. The old-fashioned or traditional hydrangeas only flower on 2-year-old wood, so early summer pruning removes future flowers.

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