GARDEN GAFFES : Potted Cacti Just Can’t Take the Heat

A cactus can’t get too much sun, right?

Wrong.

“Most people associate cactus and succulents with full, hot, blazing sun,” said Richard Hipp, owner of House of Cactus in Stanton. But when home gardeners leave their potted cacti and succulents out in the summer sun, Hipp said, the results are often scarred and unhealthy plants.

In the wild or planted in gardens, roots of such plants are kept at a relatively cool and uniform temperature, even when the plant above is baking in the hot sun; in pots, though, the roots are not so well insulated and can easily overheat.

“The plants do burn,” Hipp said. “Our California sun is just a little brutal for potted plants.”

Hipp recommends giving potted succulents and cactus full morning sun, then moving them to filtered sun in the afternoon. “The plants will be a lot healthier and prettier,” Hipp said.

Potted roses need more water--The combination of pots and warm weather can also prove troublesome for roses. Many people don’t realize that potted roses require more water than those planted in the ground, especially when the weather grows warmer.

“Every time there’s a heat wave, I get a bunch of calls about leaves dropping and spider mites,” reported Mike Morton, co-owner of Country Bloomers Nursery in Orange. Potted soil loses water quickly, leading to stressed plants that are more prone to those afflictions as well as mildew and other problems.

“They’ll read that roses shouldn’t be overwatered,” Morton said about gardeners, but that does not apply as strongly to potted roses.

Morton recommends watering every day when the mercury climbs above 75 or 80 degrees and also that home gardeners consider a drip watering system with battery-operated timer. Because runoff water carries nutrients from the soil, potted roses also need to be fertilized more often than those planted in the ground.

Proper pruning is essential-- As a horticultural consultant for Roger’s Gardens in Corona del Mar, Cristin Fusano has seen it all, from underwatering to overfertilizing, from misuse of spray pesticides and fungicides to “putting shade plants in the sun and sun plants in the shade.”

One of the chief problems she sees on visits to home gardens is poor pruning, especially pruning at the wrong time.

Often, plants are allowed to become “leggy” and overgrown only to be cut back suddenly to the bare branches--just as the cold weather hits. “The poor plant is forced to work overtime to put out new green leaves,” Fusano said.

Many plants need to be pruned regularly, but there is a right time--and a right way--to do it, she said. The timing varies from plant to plant, but in general spring is a good time. The best bet is to do a little reading before heading out with the shears.

Let there be (the right kind of) light--The proper care of house plants is practically a science in itself, but many indoor gardeners doom their efforts from the start.

“People buy the wrong plants for the wrong light,” said Eddie Smith, co-owner with his wife, Debra, of the Plant Stand in Costa Mesa, interior plant specialists. Many plants require abundant natural light to thrive, he said, while others can get by on fluorescent lighting.

Palms, for instance, need natural light, while the hardier dracaenas (including the popular corn silk plant) can survive under indoor lighting and infrequent watering.

Where a plant will go--and what the lighting conditions will be--should be considered before buying an indoor plant, Smith said. He recommends getting professional advice on buying the right plant for the right conditions.

The bark of the dogwood--The staff of Tree of Life Nursery in San Juan Capistrano, specialists in California native plants, came back with a less-than-serious response when asked to make a suggestion for this column: “Many gardeners create confusion in the garden by planting the dogwood too close to the cattails,” reads the written reply. “This, however, is not as great a problem as it seems, because the dogwood’s bark is worse than its bite.”