The azalea bushes I have are about 15 yrs old (they were put in when we had the
house built). They have gotten very big (we have trimmed them back some over
the years).

They just don't seem to be full and full of flowers like they were when they
were the first couple of years. Is there anything I can use on them now to
help them get "fuller". I would say our soil is kind of hard where they are
planted but we do mulch around the plants.

Good old compost, an acidifying fertilizer (I like Hollytone very much) and
sufficient moisture will work wonders.

Dave

"Mceezee" wrote in message
...

The azalea bushes I have are about 15 yrs old (they were put in when we
had the
house built). They have gotten very big (we have trimmed them back some
over
the years).

They just don't seem to be full and full of flowers like they were when
they
were the first couple of years. Is there anything I can use on them now
to
help them get "fuller". I would say our soil is kind of hard where they
are
planted but we do mulch around the plants.

Mceezee wrote:


The azalea bushes I have are about 15 yrs old (they were put in when we had the
house built). They have gotten very big (we have trimmed them back some over
the years).

They just don't seem to be full and full of flowers like they were when they
were the first couple of years. Is there anything I can use on them now to
help them get "fuller". I would say our soil is kind of hard where they are
planted but we do mulch around the plants.

really can't imagine what hard soil is but it sounds inhospitable. If
you like transplant them after they bloom into fresh soil. I've never
seen an azelea object to being moved. I wonder if some fast growing tree
has shaded them past tolerance?

TK

The azalea bushes I have are 15 yrs old (they were put in when we had the
house built). They have gotten very big (we have trimmed them back some over
the years).

Failure to set flower buds may be a sign of too much health and vigor
in a plant. One solution my be to prune the roots by cutting around
the plant with a spade or moving the plant. This will check foliage
growth and encourage production of flower buds. Application of
nitrogen rich fertilizers are the main cause of vigor which suppresses
flower bud production. Deadheading flowers as soon as they wilt can
promote flower bud production. Too much shade, a cool wet summer, or
inadequate phosphorus or potassium in the soil may also suppress
flower bud production. There are a number of other reasons for a lack
of flowers. The effect of each variable depends upon the variety of
the plant. The effects include:

* Pruning. The buds are formed in late summer and early fall so
pruning then or later is not advisable since it will remove flower
buds. New leaf buds will form in the spring, but new flower buds won't
form until the next year.

* Fertilizing. Nitrogen promotes leaf and branch growth and
discourages flower bud production. It can also force late season
growth that gets killed or stunted by frost damage. Phosphorus
promotes flower bud production and hardiness. Potassium is necessary
for well being.

* Weather. Cold weather can kill flower buds. Usually you see the
brown buds in the spring. Cold spells in the fall or spring can damage
buds that are not hardened off. Bud blast (blooming in fall or winter)
uses up good buds which are then not available at the normal blooming
time.

* Exposure. Some rhododendron need full sun to bloom and others can
take fairly dense shade. In general, the more sun the more flower buds
but also the greater exposure to damage from desiccation in summer or
winter. More shade produces more foliage and less flowers.

There are many other cultural variables that influence the plant's
health and hence, its ability to produce flowers.

Not sure if this was the secret or not, but we had 3 years of draught so my 10+
year azaleas didn't even bloom last year. Last fall, I dropped a TON of
aluminum sulphate (acidifier) around them and the hollies, watered well.
They bloomed like gang-busters this year. Azaleas bloom on new growth (seems
that way in my yard) so if they aren't putting out new growth, they may not
bloom. If the soil is that bad, perhaps a little core aeration around them
under the mulch would do some good. Not too close to the root ball I would
think, perhaps as much as 2/3 would help the plant get the fresh start it
needs.

Careful, aluminum sulphate will increase the aluminum ion content of
the soil to a point where it will start killing plants. The blueberry
industry discovered this the hard way. It is better to use iron
sulphate or powdered sulfur to increase acidity.

Also, aeration is dangerous since azaleas have very shallow roots.
You have to be very careful. It may be better to transplant rather
than aerate.

Visit my Rhododendron and Azalea web pages at:
http://www.users.fast.net/~shenning/rhody.html
Also visit the Rhododendron and Azalea Bookstore at:
http://members.aol.com/rhodyman/rhodybooks.html

Cheers, Steve Henning in Reading, PA USA