High heat spells such as the one we had last month can exert a devastating effect on gardens, but as many of us learned, it’s far worse during a drought. And worse yet when the gardener is away and the irrigation system fails, as I experienced.

In my case, the only real loss was the last of the lettuce. Tomato vines perked up as soon as drip lines were turned on, and shriveled green beans didn’t matter as soon as new beans took their place.

I could have lessened this minor damage had I laid down deeper mulch around these few vegetables. Those in other beds as well as all shrubs and perennials were better protected.

Drought, like any kind of strife and strain, can teach us lessons that we don’t learn during prosperity. When water is limited, the corollary is that plants are limited, or at least should be. The more plants in a bed, the greater the root mass vying for moisture. By reducing the number of plants, those remaining benefit.

Water-hungry vegetables, particularly those with large leaves, want more water than some of us have available this year.

My wilted squash and bitter cucumbers have told me that I should either give them more water or give up on them.

Their drip line is now turned off and the deep-rooted parsley and sage in the same bed are on their own.

Removing plants

Normally it’s a difficult decision to remove plants from a garden, but when some are struggling to survive with little relief in sight, it’s time to make changes.

I’ve removed a dwarf Chinese fringe flower shrub (Loropetalum chinense), one that I coveted then coddled for over a year, but it simply couldn’t make it with reduced irrigation. It came out along with a few stressed roses that suffered from blackspot and needed more than water.

Ten-year old, leggy rockroses (Cistus), showing their age and offering no beauty after a brief spring bloom, also came out despite their low water needs. So did a few coral bells (Heuchera) whose foliage withered from reduced moisture.

Water hogs or savers?

The roses that I took out might be the last thing that another gardener would remove despite their fungal problem. But all gardeners will have to re-evaluate which plants to favor if serious drought and water rationing continue.

Are there hostas in your garden? Grown for the dramatic effect of their spectacular foliage, these perennials are luxuriant only when the soil is constantly moist. They have no place in a dry summer climate such as ours.

Although wormwood species (Artemisia) offer a completely different type of foliage than hostas, their grayish green leaves provide striking accents against darker greens, and artemisias thrive in dry soil with infrequent irrigation.

Daylilies (Hemerocallis) are one of the most easy-care perennials and are extremely popular in home and curbside commercial gardens, but they’re at their best only with regular water from spring through autumn.

Lily-of-the-Nile (Agapanthus), a South African native, is an alternative species with strappy green foliage year-round.

New plantings require moisture during their first summer, but established plantings withstand long periods of complete drought.

Suffering succulents

Oddly enough, certain succulents thought of as water-savers actually demand sufficient summer irrigation to avoid wilting and taking on a scrappy, desiccated appearance.

Various species called hens and chicks (Echeveria and Sempervivum), for example, typically store water in their fleshy leaves in order to survive periods of drought. But when supplemental moisture is lacking, leaves shrivel and die.

Those grown in part shade fare better with reduced irrigation, with some species out-performing others. In my garden, the shabby ones with dried and dropped leaves and unattractive lanky stems are gradually being removed.

However, larger, more drought-tolerant succulents such as agave and yucca continue their good looks and remain plump and pleasing during dry periods.

Moving plants

When moving plants at any time, whether from a pot to the garden or from one bed to another, microscopic root hairs always suffer some damage.

In moist conditions, roots regenerate these minute structures fairly quickly and water absorption merely slows. But in drought conditions, plants may become dehydrated and won’t survive being transplanted because of root damage.

As autumn approaches and we face the traditional time to plant, divide, and transplant, we may have to delay those activities until enough rain encourages routine gardening.

Rosemary McCreary, a Sonoma County gardener, gardening teacher, and author of Tabletop Gardens, writes the monthly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402.