To Deadhead or Not to Deadhead...

When and how to deadhead is a common question for gardeners. 

The phrase Dead Head has a whole different meaning for those of us who are gardeners, rather than the general public out there.  If you google either Dead Head or deadhead the search results will return information on fans of the Grateful Dead not the act of removing spent blooms from plants.  It takes typing in ‘Gardening Deadhead’ to get results that will be helpful in learning more about keeping plants in bloom.

I am often the person who answers questions sent in by gardeners and recently one of the most common questions has been when and how to deadhead specific plants.  In this article I will give a brief summary of why deadheading is sometimes necessary, how you should deadhead, and which Proven Winners plants need deadheading.

First what exactly is deadheading?  This gardening term simply means to remove the old spent blooms from a plant to help keep plants blooming longer. 

Your next question is likely to be “Why does a plant bloom more if you remove old flowers?”  In the grand scheme of things flowers are meant to insure survival of the species.  All of the various blooms that nature developed (not plant breeders) are an attempt to insure that seeds are produced and the next generation of plants is developed.  In some cases once seed has been produced, thus ensuring the survival of the species, the plant will stop blooming.  There is no reason to put energy into blooming any longer.

A gardener probably figured out that removing old flowers before they produce seed will keep the plant blooming longer.  This can be a rather time consuming endeavor, but many times is considered a labor of love. In more recent times plant breeders have put a lot of effort into increasing the blooming time of plants. Someone then figured out that sterile plants, those that do not produce seed, will bloom continuously even though you don’t deadhead.  These plants keep on trying, unsuccessfully, to produce seed.  Rather frustrating for the plant but easy for the gardener.

As time has gone on plant breeders have put a lot of effort into choosing plants that will continue to bloom without deadheading.  Sometimes this is because the flowers are sterile and sometimes it is simply because it is possible to choose plants who are prolific bloomers despite setting seed.  Proven Winners tries to select plants that are prolific bloomers but still are “low maintenance,” which generally means that they don’t need to be deadheaded.  Another part of  “low-maintenance” refers to the fact that many of our plants are “self-cleaning”.  This simply means that wind or other factors will cause the flowers to either blow off the plant or simply melt away leaving no old flower to remove.  Now if only my car was self-cleaning!

Choosing plants that don’t need deadheading would certainly be the easiest route to continuous flowers.  However, in some cases there will be a plant you can’t do without, even though deadheading is required, or perhaps the sight of old blooms still hanging on to plants will be unsightly enough that you want to remove them anyway.  In these cases knowing how to properly deadhead will be necessary.

In most cases when deadheading you can simply remove the old flower by pinching off the stem just below the base of the flower.  This will remove the old flower and keep it from producing seed.  If the flower stem is large or you don’t want to stain your fingernails green, you may find using pruning shears or a scissors to be a better choice. 

With larger stems removing just the flower may leave an ugly stem exposed.  Any flower can be removed just above the first leaf below the flower head without affecting the rest of the plant.  For plants that bloom with spikes of flowers this would be the preferred method.  New research has recently shown that even roses perform better when old flowers are removed just above the first leaf rather than at the first set of 5 leaves. 

While a good rule of thumb is always nice to have, a list of how to deadhead specific plants will be useful too.  Below is a quick run down of our Proven Winners plants and some notes on deadheading.

 Deadheading not necessary for Continuous Bloom 

Ageratum ‘Artist^®’ – they will “bury their dead” (this simply means the new flowers will quickly cover the old flowers) so no dead heading is necessary.  This is not true of other series of Ageratum

Angelonia ‘Angelface^®’ - self-cleaning

Argyranthemum – removing old blooms may improve appearance.

 Aster ‘Sapphire’ – self-cleaning 

Bidens – self-cleaning

Bracteantha ‘Sundaze^®’ – removing old blooms may improve appearance

Calibrachoa ‘Superbells^®’ – self-cleaning

Diascia ‘Flying Colors^®’ – self-cleaning

Euphorbia ‘Diamond Frost^™’ – self-cleaning

Euphorbia ‘Efanthia’, ‘Helen’s Blush’, ‘Kalipso’ – These plants begin blooming in early spring and by late spring to early summer they are done.  Deadheading won’t keep them blooming longer.  However, removing the old flowers once the plant has finished blooming will encourage the plant to branch more and the next spring you should see an increase in flowers thanks to a better branched plant.

Gaura ‘Stratosphere’ and ‘Karalee’ – each flowering stem adds blooms, continuously to the end of the spike. As time goes on the flowering stems can get rather long and tangled.  Although deadheading isn’t necessary for continued blooming you may find that you prefer to trim back some of the flowering stems at some point in mid-summer.  This will encourage new flowering stems to emerge.  Flowers will be closer to the foliage and the plant will look tidier.  If you choose, you can trim all the flower stems off at once, however, you should then expect a 2 to 3 week period without flowers.

Geranium ‘Jolly Bee’ – self-cleaning

Gypsophila ‘Festival Star’ – It should continue to bloom without dead-heading but removing old blooms may encourage additional blooming.  With any Baby’s breath the more you use as a cut flower the more the plant branches and re-blooms

Heuchera ‘Dolce^™’ – They begin blooming in early spring.  Deadheading won’t keep them blooming longer.  However, removing the flower stems once the plant has finished blooming will keep them looking tidier.

Heucheralla ‘Strike it Rich^™’ - They begin blooming in early spring.  Deadheading won’t keep them blooming longer.  However, removing the flower stems once the plant has finished blooming will keep them looking tidier.

Lamium ‘Pink Chablis’ – self-cleaning

Lantana ‘Tropical Fruit^™’ – self cleaning

Leucanthemum ‘Broadway Lights ^™’ – Deadheading isn’t necessary but removal of old blooms may improve the appearance of the plant.

Lobelia ‘Laguna^™’ – self-cleaning

Lysimachia ‘Snow Candle’ – remove spent flower heads for additional branching and re-flowering on new branches

Mecardonia ‘Goldflake^™’ – self-cleaning

Nemesia – self-cleaning

New Guinea Impatiens ‘Infinity^®’ – self-cleaning

Onothera ‘Lemon Drop^™’ – self-cleaning

Osteospermum ‘Soprano^™’ and ‘Symphony’ – “bury their dead”

Oxalis ‘Charmed^™’ – self-cleaning

Penstemon ‘Lilliput^™ Rose’ – self-cleaning, old flower stalks may be removed if deemed unsightly

Petunia ‘Supertunia^®’ – self-cleaning, this is not necessarily true of all Petunias.  You may want to remove old blooms of ‘Supertunia’ doubles since these larger flowers sometimes remain on the plant.  Leaving them will not affect flowering.

Phlox ‘Intensia^®' - self-cleaning, this may not be true of all phlox

Pulmonaria ‘Gaelic^™’ – self-cleaning

Sanvitalia ‘Sunbini^®’ – “buries its dead”

Scaevola ‘Whirlwind^™’ and ‘New Wonder’ – self-cleaning

Sedum ‘Garnet Brocade^®’ – the seed heads will remain on this summer to fall blooming plant.  Removing them will not keep the plant blooming longer.  Many people consider the seed heads to be attractive and will allow them to remain on the plant throughout the winter before removing them as part of their garden spring cleaning.

Sutera ‘Snowstorm^®’ and ‘Cabana^™’ – self-cleaning

Stachys ‘Sentimental Journey^™' - self-cleaning

Tiarella ‘Stargazer^™’ - They begin blooming in early spring.  Deadheading won’t keep them blooming longer.  However, removing the flower stems once the plant has finished blooming will keep them looking tidier.

Torenia ‘Catalina^™’ and ‘Summer Wave^®’ – self-cleaning

Verbena ‘Babylon^®’, ‘Tukana^™', and ‘Superbena^®' - self cleaning