Pinching Back Flowers on Basil
Answered by: Conrad Richter
Question from: Jessica
Posted on: June 2, 1998

I’ve always heard that you should remove the blossoms from your basil plants before they bloom in order for the plant to keep producing more foliage. However, whenever I clip back the flower buds on my Holy Basil plant, it ends up getting straggly and sickly-looking. Is this really the best way to make your plant produce more greenery? I use my basil often in my cooking and would like to keep it growing healthy and fast.

Pinching back flowers does help extend the lifespan of many plants with limited lifespans. These can include annuals, biennials and even some perennials. For example, if you don’t cut back the flowers on angelica before the seeds form, plants sometimes do not survive another year.

To understand why this is true it helps to remember that the goal of plants is to reproduce. Once a plant flowers and sets seeds, its goal is accomplished. A complex set of hormonal signals marshalls resources toward producing viable seeds so the next generation can have a good start. The rest of the plant, including leaf and stem growth, becomes of secondary importance because seeds represent the future. Typically, in plants with limited lifespans, plants in flower and seed lose their vigour and become susceptible to disease, and eventually die.

The annual basils are known to deteriorate quickly once seeds are set. Many authors suggest that pinching the flowers at an early bud stage will prolong the life of these plants. Sometimes it is possible to trick an annual basil into growing another half season or more. However, the senescence response begins even before the flower buds appear, so pinching the flowers only helps to lessen the senescence response in these plants, but does not eliminate it completely.

Your basil plants are probably living longer than they would otherwise without the pinching, even if they do not look as vigourous as they once did. But, you can never prevent the decline completely.

You may want to experiment with nutrition. Plants tend to go to flower more readily when nutrients are in short supply. They get ‘scared’ and try to accelerate the flowering and seed formation stages in order to ensure the survival of the next generation. If you feed with a higher nitrogen fertilizer (first number highest – e.g. 10-5-5) you may be able to delay the flowering response somewhat. Keeping the plant evenly moist and making sure that the roots have room to grow also helps. Reducing the light intensity with a fine netting may help keep the plants in the vegetative state.

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