Container math: Divide your roots to multiply your plants

By the month of November gardeners and gardening goals have moved indoors. Make this the winter you improve your air quality and mindset by growing more houseplants. Frugal gift givers can even take cuttings of favorite houseplants to pot up as gift plants or to use to create dish gardens or terrariums.

Here are the steps to horticultural math: divide to multiply or get snippy to make more babies.

Dividing houseplants

Not all houseplants have the type of root system that lends itself to easy division. Look at the base of your plant for younger-looking sidekicks or new growth spreading out from the stem of the plant. Many ferns, philodendrons, pepperomia, sanseveria or snake plants, spider plants, sedums and succulents and philodendrons are easy to divide. Fiddle leaf figs and ficus plants are not candidates for division.

Timing is not everything: Yes, you may hear that the best time to divide houseplants is in early spring when they start new growth. But here in Western Washington you can divide the houseplants listed above any time of year. You will know when a houseplant really wants to undergo a transplant surgery or division when you see roots splitting the pot or growing out from the bottom or top of the container, when the plant tips over from being so top heavy or when you notice pups or side shoots at the base of a mother plant.

Step One: Water well, then turn your pot upside down, tap the rim of the pot on a table and pull out the entire houseplant, roots and all. This will make a bit of mess. Spread newspaper on your countertop first then just dig in.

Step Two: Take a moment to study the roots. You may be able to disentangle or gently pull apart new young plants from the base of the mother. Most likely you will need a sharp knife to separate and divide the roots. At this point you can also decide to cut the top half from any leggy plant and repot the bottom half in fresh soil and a slightly larger pot. Then you can try to root the stem of the decapitated plant. This works best with philodendrons and sedums that have grown leggy.

Step Three: Get a grip (on the knife and your nerves) and cut into the thick root ball dividing the plant in half if you cannot see any separate root system. You may need a serrated knife or small saw to cut into thick roots.

Step Four: One half of the plant can now go back into the original pot with fresh potting soil surrounding the roots. Firm the soil with your hands a bit and water well. Tall plants may need staking for a few months while new roots grow. The other half of a divided plant or the young pups you have removed from the mother plant can go into other containers, again using fresh potting soil, not soil from your own garden. Make sure all pots have drainage holes. Recycling plastic pots from nursery plants is fine once you wash them. You can also recycle the plastic six-packs from summer annuals. Use these to root stem cuttings. Fill each section with potting soil and poke small side shoots or cut stems (remove any leaves from the bottom third of a stem cutting) from sedums and succulents. You can also try rooting single leaves from African violets or baby ferns into the individual cells. If the new cuttings start to wilt or have no roots you can cover the young plants with a tent of vented plastic wrap to seal in some humidity.

Step Five: Who gets your gifts? In four to six weeks new roots will make your new plants sturdy enough for adoption. Slip the plastic pots into baskets or group some young plants together in a dish garden, pop a tiny fern start into an old fishbowl or check out the novelty containers sold at local nurseries. Just make sure you add a tag explaining that the plant you are giving was started by your very own green thumb – a gift impossible to order from the internet.

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Marianne Binetti has a degree in horticulture from Washington State University and is the author of “Easy Answers for Great Gardens” and several other books. For book requests or answers to gardening questions, write to her at: P.O. Box 872, Enumclaw, 98022. Send a self-addressed, stamped envelope for a personal reply.

For more gardening information, she can be reached at her Web site, www.binettigarden.com.