Fertilize And Prune Wintered Hibiscus, Mandevilla In March

Plants are highly intelligent. While humans are wishing for spring while whining about winter, indoor plants are silently and wisely responding to the increasing intensity of the March sun and sensing the lengthening daylight. Plants sense the longer days and increasing light and know that it’s time for a spring revival.

Houseplants, and especially plants brought indoors from our patios to overwinter, like hibiscus and mandevilla, realize that days are getting longer, which triggers their growth instinct.

We can help our plants, by encouraging their desire to grow. It’s important that we respond in early March by giving plants what they need so they’ll produce new, bushy growth by the time we return them outdoors to our decks, porches and patios.

Here’s what to do in early March to maximize potential for hibiscus, mandevilla and other tropicals we’ve wintered indoors.

  • Early March is the time to prune and shape plants. It’s common for a percentage of leaves to yellow and  drop during winter. Winter’s leafy growth is often spindly and stretched. A drastic cutback works wonders. On our overwintered mandevillas and thunbergia, we cut the tops back by one-half or more to encourage robust growth from the base. Hibiscus can be pruned to retain the original shape – some are trained as single-trunk trees, others are multi-stemmed and shrub-like. 
  • Remove any accumulation of yellow leaves from the plant or soil surface, as they harbor insects and disease.
  • These plants don’t absolutely require re-potting every year, but if they’ve been in the same pot/soil for several seasons, repotting into slightly larger diameter pot is a good idea. March is a great time to repot.
  • Very Important – Begin a regular schedule of fertilizing now, which provides the nutrition for the plants’ instinctive desire to grow. Fertilizing in March helps wake the plants. You might say it gives them a good breakfast to start the new school year. Water soluble fertilizers like Miracle Gro are very effective. Follow the directions (for wintered tropicals, I use the rate indicated for outdoor plants, the same used for patio plants in summer.) Fertilize every two to three weeks. Or you can fertilize with every watering with half-strength fertilizer added.
  • Be certain plants are getting enough sun. Most tropicals are sun-loving.

So the 4-part secret to success is (1) prune back (2) repot now if needed (3) Fertilize (4) give plenty of sunshine

Good luck, and Happy Gardening!