On Aug 30, 6:20*pm, "PAT AYMAR" wrote:
Why did myHydrangeastop blooming? It gets about 4ft high, nice and green
but "no blooms" anymore.

Pat

Hello, Pat. There are several possibilities to consider when a
hydrangea does not bloom. Here is a list with suggestions on what to
do. Sorry that the information is so long.

* Pruning: Pruning at the wrong time is a very common problem but,
since you have not pruned the plant, it is not the cause of your
problem. I provide the information just for future reference.

Hydrangeas that bloom on old wood (many macrophyllas and all oakleafs,
for example) develop flower buds during the months of August-
September. This is a process that starts in the Fall when temperatures
start going down into the 60s. To prevent cutting off the flower buds
for Spring, all pruning should be done after blooming but before
August.

Hydrangeas that bloom on new wood (paniculatas and arborescens are an
example) develop flower buds in Spring. The only time that you should
not prune these is when they are about to bloom and it is just for
practical reasons (you want to see the blooms, right?).

Hydrangeas that bloom on old or new wood (new macrophyllas like the
Endless Summer Series, Forever & Ever Series, Let's Dance Series,
etc), develop flower buds during the months of August-September. And
then they develop more flower buds in late Spring. If you live south
enough, you may get a third set of blooms in late Summer or early
Fall. These should not be pruned when they are about to bloom.
Deadheading promotes new blooms so feel free to deadhead during the
growing season.

When hydrangeas get more than 5 years old, they tend to produce less
and smaller blooms. To revitalize plants when they do this, prune
about 1/3 of the older (living) stems down to the ground on summer #1.
Do the next third on summer #2 and do the last third of summer #3.

* Weather: Mother Nature can be fickle and all of these things can
kill your flower buds....

If a hydrangea is planted out of zone, it will never, or hardly ever,
bloom... although it will probably have very nice green leaves. The
cold temperatures and the cold drying winds of winter may either kill
the flower buds or/and the stems on which the flower buds grow. An
example of this would be to plant a hydrangea rated for USDA Zones 7-9
in Zone 6. You know you have this problem when the hydrangea always
grows back from the ground every Spring instead of leafing out. Winter-
protection techniques will aid. And so will planting varieties that
bloom on new wood. Paniculatas do well in this environment and so do
selected macrophyllas that bloom in old and new wood.

Hydrangeas can also suffer from sporadic weather issues even if
planted on the proper zone. For example:

(a) If you get an early frost in the Fall, the plant's flower buds can
be killed, especially if the plant is not dormant yet. Fertilizing
once in June if you live in the northern states will help (hydrangeas
need very little food). Stopping all fertilization in August-September
will also help; it makes the plants go dormant in time for Winter. You
can use manure or cottonseed meal as fertilizers. So, try to stop all
fertilizing and pruning before August in order to harden any new stems
and flower buds before winter.

(b) If you get a late frost in the Spring, the plant's flower buds can
also be killed. Using winter protection techniques will help prevent
this. Removing the winter protection techniques at the right time will
also help. Unfortunately, no one really knows what "the right time"
is. You can find your average last frost date (local nurseries can
help) and add 2 weeks to that date (or add whatever amount of time you
prefer). But some times, a late frost comes really late and you loose
many or all blooms. Once these buds are lost, you will not get new
ones until next year. The exception is if you have remontant varieties
like the Endless Summer Series, etc.

So this could be what happened to you. It happened to me in Zone 8
several years ago. Temperatures were in the 70s through December and
then the bottom fell; we suddendly had freezing sub-temperatures for
almost 5 days in a row.

If you have not used winter protection techniques in prior years, it
is possible that something weather related killed the flower buds this
past winter. You can add winter protection techniques going forward or
do nothing if it does not happen often.

Maintain 3-4" of any type of acidic mulch past the plant's drip line.
This helps conserve soil moisture and protects the plant roots. If
your plant has lots of small stems because of pruning or simply
because it has, consider adding more mulch after the plant has gone
dormant and the leaves have dried out. Maybe 6-10 inches, perhaps?
Then in Spring, you can remove the mulch down to 3-4"; use the extra
mulch elsewhere in the garden or add to the compost pile if you have
one.

*Soil Moistu Try to maintain constant soil moisture, especially
from August until the plant goes dormant. Lack of sufficient moisture
from August until blooming time can cause the plant to abort the
flower buds. During warm and dry winters when the ground does not
freeze, water once every two weeks.

*Fertilizing: Hydrangeas fed an excessive amount of nitrogen-rich
fertilizer(s) will bloom very little or not at all. Some people
encourage use of this type of fertilizer to increase bloomage but
hydrangeas do not need that much fertilizer and paniculatas, in
particular, can even be grown without fertilization assuming you have
good soil. Since your comments indicate that you live in the northern
half of the country, one application of fertilizers like manure or
cottonseed meal should suffice; you can do this in June. A general
purpose slow-release chemical fertilizer with a NPK Ratio around
10-10-10 can also be used.

*Sunlight: Hydrangeas planted in really dense shade may flower poorly
or not at all. If your plants are not getting any direct sun, consider
if the amount of indirect sun is enough. I have some hydrangeas in the
front of the house that are always on the edge of the house's shadow
but, being at the edge, they get lots of reflected light and have no
problems blooming.

Finally, planting other varieties is an extreme solution that you can
consider as well if the cause of the problem is weather related. The
Endless Summer Series, Forever & Ever Series, Let's Dance Series, etc,
for example, are very popular in the northern half of the country
because they bloom on old and new wood. The plants develop flower buds
in August-September, just as other macrophyllas do. But then they
develop new blooms again in late Spring. With these plants, if Mother
Nature kills the blooms during winter, new blooms arise in late
Spring.

I hope that gives you clues as to what could have happened and what
can you do, Pat.
Luis