Purple waffle plants (Hemigraphis “Exotica”), named for the highly textured maroon foliage, add a tropical touch as houseplants and can be grown outdoors in the US Department of Agriculture plant hardiness zones. United 10-11. Once this relatively low-maintenance plant is properly established in a bright, wet spot, regular care will help improve its appearance and increase its resistance to pest infestations.
Purple waffle plants require moderately moist soil year-round to keep their foliage lush and healthy. In summer, water is when the soil feels just 1/4 inch wet below the surface. Water deeply but infrequently, add water until it drips from the drainage holes at the base of the pot. In winter, the soil will take longer to dry out, so water it less often. Closely monitor soil moisture and water only when 1/4 inch below the surface has dried. Always use filtered or demineralized water when watering purple waffle plants to avoid an accumulation of excess salts in the soil.
Overfertilization of purple waffle plants often causes weak, thin growth that detracts from their naturally lush and vibrant appearance. Feeding a weak fertilizer solution monthly during the growing season will help keep the plant growing vigorously, especially if it is in a pot. Dilute 1 teaspoon of general-purpose fertilizer, 20-20-20 ratio in 1 gallon of water. Replace one watering per month with the fertilizer solution, being careful not to splash the leaves. Purple waffle plants benefit from a rest period during the colder months, so stop feeding in the fall to allow the plant to come to rest.
Pruning and grooming
Purple waffle plants sometimes develop minor cosmetic problems. The most common problem is spiny or dead, damaged growth. Prune unwanted stems at the base whenever they appear. Before use, soak pruning shears in undiluted household disinfectant for five minutes and rinse well before use. Disinfecting the scissors prevents the spread of the disease. Purple waffle plants require high humidity and can develop leaves with crisp edges if the air is too dry. Daily misting will help correct the problem, as will regular watering. Use demineralized water to prevent white spots from appearing on the leaves.
Purple waffle plants suffer from a few serious insect problems, although they can develop minor infestations of whiteflies and scale insects. Problems show up on the underside of leaves, where cotton matter and molasses sap often appear. Advanced infestations can cause leaf burn and stem death. Treat scale or whitefly infestations with a ready-to-use insecticidal soap spray. Spray the solution on the top and bottom of the leaves every four to seven days until the insects are gone. Rinse the leaves with clean water a few hours after each application to reduce the risk of injury. Follow the directions on the label as they vary by brand