Flowers are wonderful. They fill our lives with color, help provide us with food and ensure plants can reproduce. Gardeners, whether they grow ornamentals or vegetables, try to encourage flowers on their plants.

However, flowers are not always a positive in the life of a plant. There are times when a gardener, especially one who is growing vegetables and fruit, will want to remove flowers from plants and keep that process from happening.

And ornamental growers will need to remove flowers on many plants once flowering ends.

Why do we need to do this? Isn’t it counter-intuitive?

I stroll up and down the aisles at the market or at the garden center and see large tomato and pepper plants with flowers and sometimes even fruit on them.

More often than not, I see people leaving the market with these plants destined for their home gardens. Unfortunately, these folks are headed for disappointment if they are planning on planting these already-producing plants in their garden.

To understand the issue, we first need to understand a little about how the plants work and how they establish themselves.

The fact of the matter is that producing flowers and fruits are tasks that take large amounts of energy. Unlike animals, which can increase food consumption to meet increased energy demands, plants are at the mercy of the amount of energy they can produce on their own.

Plants can’t speed up the process, so they have a finite amount of energy to work with. If there’s lots of energy being devoted to producing flowers and fruits, there’s less energy directed toward general plant growth. This is especially key in newly transplanted plants — they need to establish roots as quickly as possible, a process that also takes energy.  These developing plant parts are referred to as energy sinks.  Mature leaves, the part that produces the energy, is referred to as the energy source.

It is important to remember this energy usage when planting new plants in the garden — they’ll establish much quicker if they don’t have the task of blooming and producing fruit.

While it is important for perennial plants, it is paramount for annual plants. Yields will be greatly reduced if you buy an annual, such as a tomato or pepper, already in bloom.

Once you get it home and ready to add to the garden or to a container, the flowers and fruits have become an energy sink, stealing away the energy needed for new roots to establish. This is why it is key to NOT buy annual vegetables that have already started blooming.  If they have, be sure to pinch the flowers out when you plant them.

And while we have been conditioned to shop for flowers that are already in bloom, you’ll also get better growth and establishment from plants that aren’t in flower when you buy them.

As for perennial plants, fruit plants like strawberries and trees such as apple and peach should not be allowed to flower in their first year, to direct more energy to growing roots. In fact, you should remove any flowers from fruit trees during the first few years.

While it isn’t commonly suggested, you’ll also have bigger perennial flowers in the following years if you don’t allow them to flower in the first year they are planted.

Ornamental plants, though, will benefit from deadheading once the flowers begin to fade. We don’t often think of our favorite flowers as producing fruit, but they often do. (That’s the purpose of flowers, to produce fruit for reproduction)

Even if you don’t notice it, those annual and perennial flowers typically produce some sort of fruit or seed once the flowers finish. If it isn’t something you wish to save seed from, remove the flowers once they fade.

Otherwise, those fruits and seeds they produce will be taking energy away from the plant. You may not notice it now, but removing that energy sink will result in much healthier and heartier plants in the future.

So remember, for best results, let those plants bloom where they are planted (and not a moment before). You’ll have more tomatoes and healthier flowers if you stick with the late bloomers. You won’t do yourself any favors by buying plants that have already started flowering.

Sources

Source-Sink Relations in Plants (Wageningen University Plant Physiology)

Alonso-Blanco, C., Aarts, M.G., Bentsink, L., Keurentjes, J.J.B., Reymond, M., Vreugdenhil, D.and Koornneef, M. (2009). What Has Natural Variation Taught Us about Plant Development, Physiology, and Adaptation? Plant Cell 10.1105/tpc.109.068114

Foyer, C.H.,  and Paul, M.J. (2001) Source-Sink Relationships Encyclopedia of Life Sciences, Nature Publishing Group

Originally published May 23, 2016 on UrbanGardenGuru- John Porter.

John Porter

Urban Agriculture Program Coordinator at Nebraska Extension

John Porter is the Urban Ag Program Coordinator for Nebraska Extension and Nebraska College of Technical Agriculture, serving both as an extension educator and professor of urban agriculture. He specializes in urban agriculture and horticulture, especially in the areas of vegetable and fruit production for home gardens and urban farms and edible landscaping.