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Deadheading – the Secret to Better Flowering Shrubs

June 24, 2019

Written by Dave G.

We all want the best plants in our gardens – healthy bushes covered in flowers that bring color and often perfume for us to enjoy. Yet sometimes we are disappointed. A bush produces a few initial flowers and then stops for the rest of the season, or has a good flowering one year, and then little or nothing the next one. Instead of just being disappointed, there is something you can do. It is called ‘deadheading’, and it is just what it sounds like – the removal of dead flowers and flower clusters once they have finished producing flowers. With plants with large flowers, like roses, for example, we may remove the whole flower. More often we do this with plants that produce their flowers in clusters or heads.

Of course, not all plants can be effectively deadheaded – imagine trying to do a flowering cherry for example! But lots can be, and besides making your garden look tidier, this practice, which you will see experienced gardeners doing, is the secret to keeping your plants blooming profusely.

Why Deadheading Works

Plants don’t flower for our pleasure of course, they are driven to do it by the need to reproduce, and fertile seed is the goal. So after flowering the plant puts its energy into producing as much seed as possible, and since seed is a storehouse of goodness for the future baby plant, it takes a lot of the plant’s resources to make those seeds. By removing the flowers we divert those resources into new growth instead, to put it in human terms, we ‘trick’ the plant into wanting to make more flowers, since its drive to make seed has been frustrated. The extra available nutrients mean that the plant has the resources for those flowers, either this season or to prepare for the next one, and, bingo! More and larger flowers are made.

Some plants will respond by making those flowers this year, either by flowering continuously, or by having a second crop later in the year. Others are locked into a ‘one a year’ flowering pattern, but with plenty of resources available they won’t skip a year, as some plants will do after profuse flowering and seeding.

How to Deadhead Correctly

Deadheading is simply to do. You need a sharp pair of pruners (secateurs) – and that’s all. Since our goal is to prevent seed production, the sooner we remove the spent flowers the better. With individual flowers like roses it is best to remove them when the petals are beginning to fall. (That also saves a lot of mess to clean up). With flowers in clusters, once the last few have faded, or sooner if you are finding it already unsightly, you can remove them. A lot of the value is lost if you wait until the seed pods are swelling, so get in quickly, and get it done. The goal is to remove just the flower, although in practice we often remove the first leaf. If you remove a lot of foliage you weaken the plant, and spoil the benefits, and in some plants the lower buds will only make new shoots, not flowers. Try not to leave a stalk, because this will turn brown and die, and it can look unsightly. Try to cut just above a bud or a leaf, where new buds grow. It’s easy!

Some shrubs are just too large to adopt this method, and then it is time to trim with hedge shears or hedge trimmers. By doing this right after flowering you remove the potential seed heads, and you also leave the longest season possible for flower buds to develop for the next year, so it works out really well.

Plants that Benefit from Deadheading

Almost all plants benefit from deadheading if our goal is more flowers, but for some it is not practical. Usually we do this with large flowers, or large clusters of flowers. Let’s look more closely at some of the plants you can deadhead, and that show the most benefit.

Lilacs

Lilac bushes are one of the highlights of spring, but they also produce unsightly seed heads, and besides the untidy look, leaving seed heads often causes your bushes to flower every second year – not at all what we want. On larger bushes this can be a little tedious, but even if you don’t get them all, it all helps. Remove the flowers as soon as they become unattractive, and don’t wait until they look like seed pods.

Rhododendrons

Large flowering rhododendrons also produce big seed heads, and if not deadheaded the quality and quantity of flowering suffers. Rather than cutting it is better to snap the spent heads off. They have a natural weak-point just above where the buds for next year develop, and if you bend the head to one side it will snap of cleanly. It’s quicker this way too.

Roses

Roses are flowers that respond really well to being deadheaded. They will produce many more flowers if you do this, so it’s really worthwhile. Cut the flower head just above the first full-sized, complete leaf – sometimes there are small leaves up on the flower stem, and those won’t produce buds.

Crape Myrtle

There has been a profusion of new varieties of Crape Myrtle in recent years, and this is a plant that can be encouraged to produce more flowers almost continuously if it is deadheaded. The flowers bloom in succession within a flower head, but once the last couple have faded, get out those pruners and remove them promptly. Since Crape Myrtle also produces seed heads that are attractive, and add some winter interest, don’t deadhead the last blooms of the season, as we get close to the first frost.

Plants that produce unwanted fruit or seeds

While we often want seeds and fruits for winter color and interest, there are some plants where these are not very attractive, or worse, where the seeds produced become a nuisance in your garden, sprouting up everywhere. Even more of a problem, the seeds of some trees and shrubs escape into surrounding areas, making them invasive, and threatening the ecosystems around your home. With these plants – and privet is a good example – the flowering may be attractive, and feed bees and butterflies, but we don’t want the seeds. So deadhead them once blooming has finished, and wow, no seeds sprouting everywhere. When these are larger plants, trimming as mentioned earlier is the best technique to use.

Plants that shouldn’t be deadheaded

This is an easy one, but over-enthusiastic deadheading can rob our gardens of future beauty. Lots of plants have attractive berries and seed pods, and since these are around in late summer and fall – and even into winter – we really appreciate them, since they bring color and interest exactly when there are few, if any, flowers around. It is obvious that a plant that produces berries will make them from its flowers. If we remove them because of a week or two of untidiness from dying flowers and falling petals, we will miss out. So sometimes we need to be a little patient with our plants and give them a chance to move through their natural cycle. Trimming and clipping at the wrong times not only affects flowering – which we will already talked about – but it can interfere with berry and seed-head production too.