Tips for watering your garden when summer’s heat has left your soil parched

This time of year, watering takes more patience as soils may become “hydrophobic,” or so dry that they actually repel water.

If water runs right through your hanging baskets, or if you notice ground covers, shrubs or perennials that are wilted from dry soil, apply the water slowly. A slow running hose around the roots of plants or a sprinkler left on for hours until the water has penetrated the soil to the depth of the roots is the best way to water hydrophobic soils.

Hanging baskets that have dried out can be left to soak in a full bird bath or tub of water until the soil is saturated. When hand watering, take advantage of capillary action that will pull water down deeper into the soil if a second application of water follows a first.

To do this, water each area around the roots of thirsty plants then wait 15 minutes or so and water again. Dig into the soil to see if the root zone is dark from moisture.

In the garden, watering less often, but watering deeply is better for your plants than daily watering. Roots will follow moisture and if you train your plant roots to grow deep, they will be less dependent on you for supplemental water.

Q. I have a trumpet vine with orange flowers. It has been in my garden for a number of years but now I am seeing new shoots of this plant popping up in other parts of my garden. Should I get rid of this vine so that it does not take over the entire yard? — P.P., Email

A. Trumpet vine, or Campsis, is usually belting out late summer blooms in Western Washington, not taking over real estate, since our usually cool summers slow down the growth of this heat-loving vine. I suspect the last two very hot summers have inspired your trumpet vine to take off in new directions.

You should uproot the new sprouts as soon as they appear, and if your vine is growing too fast, a severe pruning now should silence some of the out-of-control growth.

You can maintain a better behaved vine by cutting growth back by one third each spring. Then every few years shorten the main stem of your trumpet vine to within 1 foot of the ground in the summer.

Like many strong-willed kids and pets, a firm hand and defined boundaries can keep those “out of control” tendencies in check.

Q. My heucheras are getting brown splotches on the leaves and I think it must be sun burn. What can I do to prevent this? — W.G.B., Tacoma

A. Heucheras are one of the heavenly “H” plants that I like to promote, along with hellebores and hydrangeas because these low-growing foliage plants come in so many colors and look good pretty much all year long.

New varieties of heucheras keep popping up with different degrees of sun tolerance. I suspect the brown leaf splotches are indeed sunburn and most likely you have a heuchera with lighter-colored leaves.

Rather than try to provide shade for your heuchera during hot summer days, move it to a new location instead. Heucheras do great in containers, rock gardens and shaded woodland settings as long as they have good drainage.

I get snippy with my heucheras after they send up blooming spikes. Then in the spring I tear apart mature heucheras and replant the offspring sprouting from the sides of the mother plant. You also should cut the long stem of mature heucheras back in the spring to promote bushy plants without giraffe necks.

One more tip: Heucheras are simple to start from cuttings. Just snap off a long stem, remove the lowest leaves and poke the cut stem into moist soil.

Q. I have a snapdragon plant that is covered with brown spots. It is looking rather dead. Is there anything I can do to save it? — D.S., Olympia

A. My sympathies. Sounds like your snapdragon has a rust infection, and this fungus among us loves to infest hollyhocks and snapdragons during hot, dry weather.

Preventing rust from ruining your late-summer bloomers is much easier than trying to control rust once it arrives. You can try cutting the plant to the ground and waiting for fresh new growth, or if the plant is valuable, such as a hanging basket full of trailing begonias, then try a fungicide spray following the instructions on the label.

Keeping your plants healthy and well-watered is the best way to reject rust on your plants. One suggestion for rust prone plants is to spray the foliage with water every few days in an effort to rinse off the rust spores.

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