Do perennial shrubs have a life expectancy? (flowers, grown, fertilizing)

[Mattie]

My hydrangeas, roses and rhododendrons seem to take longer to flower each year, despite fertilizing and watering. Do perennial shrubs have a long, but not endless life expectancy? I'm trying to decide whether or not to pull them out and start anew. They were all planted about 10 years ago.

[theoldnorthstate]

here in florida, perennials tend to wear out after about 15 years or so. But some in northern climes may last many years.

[Butterfly4u]

Matti,
Yes. Trees and shrubs have a life expectancy.
Roses can live for over 100 years.
Some roses in some grave yards have been there for 150 years.
They are the original roses, the old style, still around.
The other shrubs, not sure. I don't think hydrangeas
are love livers. Don't know about Rhododendrums.
They might need some rejuvenating pruning alsong with
some fresh composted manure to pep them up a bit.
If you are tired of them, just pick out some new shrubs
for a different look if you would like.
There are always new shrubs out and you might like
different colors.
Change is good sometimes.

[azoria]

Take longer to flower? What do you mean?

Yearly weather conditions will affect flowering times. We have hydrangeas flowering right now that have not in 5 years ever flowered before July. But we did have 2 weeks of very warm weather this month. They decided to flower.

Plants do have life spans. The shrubs you mentioned should be in their prime at 10 years old. Do not pull them out. Rhododendrons will live for many decades and so will hydrangeas. Roses, depends on the kind.

Rhodies get leggy and sullen every so often and need to be severely pruned back. According to your own judgement, if your rhodies do not bloom well this spring and look haggard, after they flower give them a very hearty cutting back. After such a cutback they probably will not bloom for two years but the the bush itself will look much healthier.

Hydrangeas will not bloom the next spring following a severe pruning. Did you cut back your hydrangeas last year?

Mulch is good. Fish meal is good. Weather is always a wild card.

[kinkytoes]

I agree with everyone who says shrubs do have a lifespan...for instance brambles often live for 10 years according to my "Fruits&Vegetables" handbook (Moore). I did read someplace that you can extend the lifespan of trees if you prune them.

Perhaps that works for shrubs, too.

There are special techniques for pruning depending on the types of hydrangea you have. I would suggest pruning the shrubs and see if they show a little more "life." next season.

But I know how the OP feels. I was soo tempted to eradicate the three gigantic, woody, NON-flowering lilac bushes planted by a previous owner.

Ok, the plants did flower...pitifully and sparsely.

I pruned these guys a teensy bit aggressively a few weeks ago...hopefully they'll do better next year. I'm not overly tolerant of shrubs that are not edible, native or evergreen.

[J&Em]

Originally Posted by Mattie

My hydrangeas, roses and rhododendrons seem to take longer to flower each year, despite fertilizing and watering. Do perennial shrubs have a long, but not endless life expectancy? I'm trying to decide whether or not to pull them out and start anew. They were all planted about 10 years ago.

Not sure what brambles and vegetables have to do with it but all three of the shrubs you mention have specimens that have lived for 100+ years. Unless you live in a difficult environment 10 years is not very long for the majority of shrubs and trees grown in much of North America. I think Azoria was on the right track with what some of the problems might be. As theoldnorthstate said in his area (FL) the tropical nature of the area probably does effect plants and shrubs on the edge of their zone enough for them to loose vigor more quickly. It's why experienced gardeners will try to look for more native species that have survived the local conditions on their own for years. It's very tempting to plant the familiar plants from other places but they don't always do so well.

When you say taking longer to flower have you actually been keeping records and know this or is it that it just seems that way? Even weakened shrubs and perennial plants will attempt to flower "on time" even if not very much, but the timing can vary a little depending on factors like rain and cold in the months before. Over this past winter many people up and down the eastern 1/3 of the country found things blooming unusually early or even completely out of their normal season. This followed unusual summer heat, a cold snap and then more very warm weather for the fall and winter months.It tricked the plants into chemicals that regulate growth and flowering at the wrong times. Prolonged cold nights, and cold snaps could delay blooming just as easily and damage buds before they can bloom.

If there have been fewer and fewer blooms every year you may be over fertilizing or incorrectly fertilizing, or there could be problems building in your soil that would account for lack of flowers. Many people have an unexplainable need to "feed" plants and don't realize that too much of a good thing is far worse than none. Good soil does more for a plant than all the fertilizing in the world. In order to flower a plant needs easy-to-grow-roots type ground and lots of nutrients but only in small quantities. There are tons of bacteria, beneficial bugs and fungi that make the soil healthy for plants and too much fertilizer can be just as toxic to them as some of the chemicals people always go on and on about being bad for the world.

Get a soil test done (begin with your local cooperative extension they can either give you the forms for a state lab or point you to a local lab that does this on a regular basis). This will tell you what is in your soil and what, if anything, is missing. The acidity of the soil (pH) may have been changing since you had the shrubs planted and that can change the health of the shrub. With all that regular fertilizer there might be far too much nitrogen (it is great for nice green leaves though) or a deficiency of phosphorus (plants slow or stop flowering without it and roots don't grow as much) just to name a few nutrient related changes.


You didn't say if you had pruned any of them and it can change the numbers of flowers you might see but not change the time. Many people have lost most or all their hydrangea blooms to pruning at the wrong time. You'll need to know what type you have to know when and what to cut if you feel you must prune them. Rhododendrons have the same problem if they are cut too late in the year because they begin to form buds for the next year fairly soon after they finish blooming. Roses often get leggy and do not bloom as profusely as the canes get older, so good pruning in early spring is often recommended but, again, you will need to know what kind you have to know if they need pruning and if they need pruning when to time the pruning and where to make the right cuts.

It would seem extreme to pull them out if they are otherwise looking alright.