Houseplants are more and more becoming our focus — so today I'm going to talk about some common problems we deal with and possible solutions.

Following are some reasons why plants have brown tips. After that, we'll discuss houseplant pests and then how to keep your tropical hibiscus happy:

♦There are several things that can cause brown leaf tips on houseplants, including low humidity, poor root health and excessive salts in the soil. In addition, some plants are sensitive to fluoride in water, which can cause brown leaf tips. Spider plant is one that is sensitive to fluoridated water. Flushing the soil occasionally with rainwater or bottled water helps reduce fluoride salt buildup.

Other examples of plants that are sensitive to fluoride are: Easter lilies, Dracena, Spathiphyllum (peace lily), cast iron plants, parlor palms, prayer plants and Freesia.

Perlite, the white spongy chunks in some potting soils, and some fertilizers may release enough fluoride to harm sensitive plants.

♦If you have a plant that is oozing a sticky substance called “honeydew,” it is probably infected by one of four pests: mealy bugs, aphids, whiteflies or scale.

Aphids and whiteflies are more easily identified due to their appearance and movement on the plant. Scale and mealy bugs, on the other hand, are more difficult to find by sight. These pests protect themselves with a hard shell, and the usual insecticide sprays are mostly ineffective. You can use a systemic insecticide, although it will take longer for this to work on woody plant stems.

You can remove scale and mealy bugs by hand, or discard the plant if the pests have taken over.

Spider mites and aphids can usually be washed off the plant with a stream of water in the sink or shower.

If you are moving the plant indoors from outside, be sure to treat the soil, and the plant, with an insecticide spray before bringing it in the house, or save time and trouble and repot the plant using a sterile potting mix.

♦Another pest commonly found on houseplants is fungus gnats. If you discover these little varmints around a plant, the reason may be overwatering and poor drainage. This alone can cause a buildup of these prolific pests.

Allowing the container mix to dry as much as possible is effective in killing maggots infesting the soil, but be careful not to injure a plant that needs to be moist.

Fungus gnat adults can be easily controlled with a household flying insect spray labeled for “gnats” that contains pyrethrin. Killing adults prevents more egg laying in the soil mix. (When using any insecticide indoors, even those proclaiming they are safe for humans and pets, always read and follow label directions.)

♦If you have a tropical hibiscus Malvaceae plant that you brought indoors, here are a few tips to keep it growing and healthy through the winter:

These plants are native to sunny, warm and humid tropical places, and you need to try to replicate those conditions indoors. They need three to four hours of direct sunlight a day, which can be supplemented with artificial light. Also, avoid overwatering and keep them on the dry side.

Spritz the stems and leaves often to supplement needed humidity and add a little fertilizer, especially one that encourages bloom, to the watering can whenever you water. Repot the plant in late winter or early spring.

Watch for pest problems and deal with them quickly. When spraying for pests, treat the tops as well as the undersides of the leaves.