Spring-Cleaning The Water Garden

Adapted to Texas conditions from material presented
by the American Nursery & Landscape Association

ith summer almost here, it’s time for water gardens to reemerge as refreshing focal points. Wake up your water feature with these tips from Richard Koogle, director of operations for Lilypons Water Gardens, and a member of the American Nursery and Landscape Association (ANLA).

  • Spring Cleaning. When winter is over, evaluate the cleanliness of your water garden. With diligent skimming and plant pruning, you’ll only need to drain it every three to five years. At most, never drain a pond more than once a year and do it while temperatures are below 70 degrees.

    Whether you remove decomposed debris by netting or draining depends upon the size of the pond and the amount of debris at the bottom. Netting is the least invasive method, but let’s assume there’s too much muck for this approach. Since most ponds or pools aren’t equipped with plugs, you’ll have to pump out the water with an existing submerged pump or by siphoning. Transfer most of the old water to a five-gallon bucket, clean garbage can or kiddy wading pool. As you’re pumping, remove plants. Keep them moist and out of direct sun. If you have fish in your pond, pump down to less than six inches of water to make them easier to catch.

  • A Fresh Start. Give pond walls a quick rinse. Leaving most of the algae assures a healthy pond environment. At this point, use a wet/dry shop vacuum to remove the last bit of water. Refill the pond. Wait several hours, or until water temperatures stabilize before returning fish to the pond. “Make sure there’s no more than a three to five degree difference between the old and new water so you won’t shock the fish,” Koogle says. Add a neutralizer chemical to speed dechlorinization. If you’re leaving fish in a holding container overnight, cover it with a net. This discourages hungry predators and stops koi from leaping to their dry deaths.

  • Predator Prevention. Koogle has a plan for keeping fish safe. “Predators are wading animals. Avoid having shelves or shallow areas in the pool – it should go straight down from the sides. Create some hiding places for fish and frogs. Post an owl or heron decoy near the pond and move it frequently,” he advises. Koi and goldfish are easy victims because they’re brightly colored. If you’ve experienced one koi cleanout too many, try Comet or Shubunkin goldfish with the darkest colored tops, or even minnows. Their dark grayish-brown color is a natural camouflage. While not vivid, they do add interesting movement and they eat mosquito larvae.

  • Netting Clear Results. “Most people want gin clear water”, Koogle comments. There are several ways to achieve this. Debris that settles at the bottom of a pond or pool is the archenemy of clear water. Keep it out with regular skimming. If your water garden rests under deciduous trees, place a net over it in fall.

  • The Clean Team. “At Lilypons, we control water clarity with plants as much as possible. Nitrate buildup develops naturally in ponds. Plants absorb nitrate directly from the water,” Koogle notes. Regular plant pruning enhances pond appearance and controls algae. The Japanese black snail (or Japanese trapdoor snail) is a water gardener’s friend because it eats only algae, not plants. Tadpoles, another cleaning critter, eat waste before it becomes nitrate. This natural patrol works if there aren’t too many fish, they’re not overfed, and there’s not too much debris at the bottom. “Generally the ratio is one inch of fish to five to eight gallons of water”, Koogle says.

Then, of course, there are mechanical and biological filters and ultraviolet lights to maintain clean, clear water. Garden centers and nurseries often sell these devices. Lilypons’ own catalog (800-999-5459) or is another source.

Keeping water gardens clean is a matter of preventive maintenance. Following these simple steps makes your water garden a clearly beautiful asset of your landscape.

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This article appeared in the May 2001 issue of Horticulture Update, edited by Dr. Douglas F. Welsh, and produced by Extension Horticulture, Texas Agricultural Extension Service, The Texas A&M University System, College Station, Texas