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15/07/2012 at 20:50
I am new to gardening. I seem to remember last year reading about dead heading Rhodys. So far this year I have ony removed the petals. Should I have removed the entire flower structure and if so when? Am I too late?
15/07/2012 at 21:07

This is what the ASmerican Rhododendrom Society says:

'It is desirable, with the large flowered rhododendrons, to remove the withered flower clusters after the blooming season.  This is fairly easily done as the central axis of the cluster, usually called a truss, will break free from the plant with a quick snap of the thumb pushing on the side, or can be cut off with a hand pruner.  With the smaller flowered rhododendrons and azaleas, dead-heading is labor intensive and and generally is not required.

Dead-heading is usually done to make the bush look more attractive, to reduce the prevalence of fungus and to prevent a heavy set of seed.  If it is not possible to remove the old flowers, it is usually not too detrimental, but flowering the next year may be reduced.'

This should be done when the petals fall, depending on the variety of rhodo you have. Now is surely better than not at all.


15/07/2012 at 21:51
I always remove the faded flower as they look unsightly. Just break off the short stalk the flower was on with your finger and thumb, being careful not to damage the new buds underneath. If you have the right place it snaps off easy. It is not too late. I know this sounds silly with the slightly inclement weather we have been getting, but make sure it is getting enough water as the buds will form but not flower if they dry out over the summer.
16/07/2012 at 10:02

I put some in last autumn & didn't know to deadhead, so thanks. They do look rather untidy.

Watering wise definitely worth thinking about. I noticed all my new azaleas & rhodys wilted a while ago. I guess they don't have deep roots yet & there is sadly an enormous tree in the neighbours garden right near the boundary, so it probably takes most of the water from that border. 

So in spite of the rain, watch out for watering still! Same with camellias, I always water mine if needed now as I think that also helps them flower next year.

16/07/2012 at 17:52

It would be interesting to take the dead flowers off just half the shrub and see whether it made any difference.

16/07/2012 at 23:11
The only difference it would make is one half would look tidy and the other half untidy with brown petals and the old flower head. I prefer to have a tidy looking rhodo.
17/07/2012 at 09:21

The American Rhododendron Society (quoted above) seem to suggest that there are other reasons to do it. I can understand the tidiness argument in certain situations and as a personal preference, but plant health is a diiferent issue. I wonder if the gardeners at Inverewe Gardens and other arboretums with 10 metre high species spend a lot of time precariously swinging about taking off every last seed head.

17/07/2012 at 16:50

Obviously not, but then things are a bit different in the average private garden with limited space and the need to maximise the iumber of flowers and make every corner of the garden count.   

17/07/2012 at 19:00

Which brings us back to whether the reasons for pruning (apart from appearance) suggested by the Americans have any validity.

17/07/2012 at 21:27

Here's Millais Nurseries' advice (rhodo specialists) -

'Dead heading is the process of snapping off the spent flower truss after flowering. It really does make a difference, and gives the plant that well groomed look for the rest of the season. However in reality, it is not always possible due to the size of the plants or the size of the garden. Therefore prioritize the operation, and concentrate on your younger plants, and those which seem weak or sick.

If you do not deadhead, then the plant will waste loads of energy making big fat seedpods, and this will inhibit growth and flowering the following season.

Simply snap the flower truss off at the base, above the whorl of leaves, using your thumb and forefinger. Be careful not to break off the new growth coming through underneath. You will soon be an expert and it will certainly pay off next season!'

18/07/2012 at 23:20
Dead heading as we have been talking about is not pruning. It is simply making the plant look tidy and stopping seed heads from forming.
19/07/2012 at 09:48

Sorry, Lorelei. I originally asked whether there was any justification for the American advice (they referred to preventing fungal attack and reducing seed-set) and proposed a simple experiment to see whether dead-heading would make any physiological, as opposed to cosmetic, difference to the plant.

Losing interest in the thread, I inadvertently wrote 'pruning' rather than 'dead-deading'. Needless to say, I do know the difference!

Thanks for Millais's advice, Grandma. Again, it would be interesting to know if it's backed up by any objective research. Obviously, they have an interest in offering plants that look good.

Joe

 

19/07/2012 at 16:24

Joe, you are certainly entitled to question and test advice given, but who are you going to believe if not the specialists?

I did a bit of research into rhodo fungal diseases and found that the rhodo leafhopper lays its eggs in rhodo buds and flowers then dies when winter comes. The eggs overwinter in the flowers and hatch in the following spring. They do not do much harm themselves but their presence encourages the appearance of bud blast, which is a serious fungal disease. Deadheading prevents the leafhoppers from overwintering and hatching and so helps prevent bud blast.

I got this from an online article called 'Insects and other Arthropods' by David A Kendall on kendalluk.com and compared it with the RHS advice on Rhodos on their website.

 

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