According to the experts (I'm certainly not one of them!), the main reasons crape myrtles fail to bloom, are:

1) Insufficient sunlight. They require at least 6-8 hours of direct sunlight daily to bloom well.

2) Low soil fertility. If water stands around your trees(shrubs) when it rains, it may be leaching the nutrients from the soil, PLUS, it is cutting off the necessary oxygen supply to the roots.

3) Lack of pruning or severe pruning. They bloom on new wood each year and benefit from early spring pruning, that promotes new growth. Severe pruning will cause all of the plant's available energy to be focused on growing new branches and foliage and not into flower production.

They are fairly drought tolerant, but need adequate moisture during growth and flowering periods. 3-4 inches of mulch can help retain soil moisture. Keep mulch 3-4 inches away from trunk(s) to permit air circulation.

To correct low soil fertility, add 10-10-10 fertilizer in the early spring, beginning of growth cycle, at the rate of one pound per inch of trunk diameter.(If multi-stem, combine diameters of all). Spread around base of tree/shrub and water in well.

Hope this helps to encourage your trees/shrubs to bloom. I had the same problem many years ago and had to move 3 fairly large ones, to an area where they received more direct sunlight.

#3 is misleading, it is a BAD LANDSCAPER'S HABIT that has fooled people into believing that hatracking (annual severe pruning) of crapemyrtles is the "thing to do". NOT!!!!!!

There are examples of non-pruned crapemyrtles all over the South (many at botanical gardens and university campuses) that have been allowed to grow to their fullest beauty with NO PRUNING/HATRACKING and their flower numbers are greater than those decapitated every spring (Auburn University did a study on the number of flower heads per tree: no pruning vs. hatracked/butchered crapes).

If anything on a crapemyrtle, you tip prune off the spent flowers after their first summer flowering. That quickly leads 2-3 side shoots to grow from that tip prune and you get more flowering by early September.

Several years ago, I had a crepe myrtle come up in my yard from seed which was probably imported with mulch. I lifted it and potted it up to see what it would do. It has very small leaves and has grown healthily in every way, except it has never bloomed, despite fertilizer, sun, etc. This leads me to believe that perhaps the "parents" of today's hybrids do not bloom as easily or often as the hybrids we have all become accustomed to. You say you don't know what kind yours are. Did you plant them or were they just there when you moved in? Perhaps my experience would be a clue.

Is your soil clay or sand? It could be that if your crapes sit in a little water after a rainstorm that collectively with time the rootball and crown of the tree are progressively getting deeper and deeper with all the silt or organic matter being deposited.

Can you see if the trunk crown or the flare (where the trunk flares out wider to transition to the roots) is semi-buried under lef mold, much or just eroded clay?

donnabaskets,
I had a crepe come up from a seed once. Nothing for 3 years. The second year, worms got it. The third year my wife cut it down. The fourth year it grow about 10 feet and finally peaked over the roof to get some sun and it bloomed. This winter I moved it to a featured spot in my garden with plenty of sun. It is doing great. I also learned to love these volunteers. Last year I had about 20. Didn't want more this season, but I found 7 more so far. They vary greatly. I have one that is an amazing grower. And one that I call a crepe vine, because it is small and draping.
Problem is they can take 3 years before their first small bloom happens. It is still exciting when the first flowers appear.
Bob

Very cool story! Maybe I need to let it out of the pot! I certainly have learned to love those volunteers. I cannot tell you how many trees I have planted lovingly and lost over the years since we moved here. I finally gave up and started watching for volunteers to come up and nurturing them. I have the only redbuds in my (new) neighborhood, all of which came up from seed imported with mulch. They bloomed this year, just five years after germination. I have a tulip poplar that is only four years old that is at least 25 feet tall now! I swore off buying trees anymore.

#1 and 3 are a little misleading. I have some 30 on my properity, but I have one that was just a twig(about 6 inches) 2 years ago and I planted it in a 6 inch pot and put it near my water faucet and forgot about it really and have never pruned it. Well this year the trunk is 4 inches in diameter and is about 15 ft. tall. It is in full shade and it is in full bloom right now. Simply beautiful and to be honest, it has more blooms on it that all the rest of mine that get full sun. Happy Gardening to all and GOD bless the USA while we have one!

About 7 years ago we planted a Crepe Myrtle in a sunny spot in our yard. A well meaning friend decided it needed to be pruned and ever since then it doesn't bloom. It appears very healthy and has nice leaves on it but just no blooming. I'm not sure if there is any hope after so many years or if it would help to prune again. I appreciate any ideas.

About 7 years ago we planted a Crepe Myrtle in a sunny spot in our yard. A well meaning friend decided it needed to be pruned and ever since then it doesn't bloom. It appears very healthy and has nice leaves on it but just no blooming. I'm not sure if there is any hope after so many years or if it would help to prune again. I appreciate any ideas.

Did the pruning occur at planting or just last year? Has it ever bloomed? Often we buy cm's in bloom to be certain of the blossom color and pruning off the excess blooms before planting helps the young tree begin to establish a broader root system.
If it hasn't bloomed for all of the 7 years since planting I might suspect a soil issue where a fall and early spring feeding could be helpful.
Just remember that a 7 year in the ground tree has feeder roots that extend at least 6 feet from the multi-trunk.
Simply scratching food a foot from the trunks is not going to
do much except feed opportunistic weed seeds.
The right food, applied at the right times will encourage bud development. At the wrong time, it encourages foliage.
At least it sounds healthy.

My myrtle has always bloomed but this year it was covered with green buds that never opened up. Now that it is fall the buds are still on the tree but all dried up. Otherwise the tree is fine. What happened>