Growth rate for a newly planted crape myrtle (growing, fertilizer, butterfly)

[TXboomerang]

I just went a little crape myrtle crazy at our house because our backyard was really bland and boring, so I planted 4 crape myrtles to spice it up a bit. I planted one close to the house near our bedroom window. It is the newer "Delta Jazz" cultivar that is supposed to stay small, around 6-8 feet.

In the corners where our fence meets our neighbor's fences on either side, and in one other spot that I would like some privacy and a screening effect, I planted 3 "Centennial Spirit" crape myrtles. These are the 3 that I am most eager to see grow. They are each around 30-36 inches tall right now. I dug out a hole a little over double the size of the containers they came in and mixed some of the native dirt/clay with compost and Miracle Grow brand garden soil for trees and shrubs. Filled it back in around the trees and put about 2-3 inches of mulch on top of the soil. They are close to a 6 foot wooden fence, but not too close, and they should get at least 7-8 hours of sun each day, closer to 9 once the days are longer, and when they get a little taller than the fence they will get full sun all day.

I bought the trees at a local Lowe's, actually got them the day they came in off the truck from the nursery. They were trained to only 1 or 2 trunks, which I really like, and almost all of the growth on it is vertical.

Anyone have any experience with this cultivar and how fast it grows if maintained properly? I would like them to reach 8-10 feet tomorrow, or I guess I by the weekend would do.
Any tricks to speed them up in a healthy manner? Or do I have to tie myself to my patio chair and be patient?

[Bulldogdad]

In my experience the smaller cultivars are usually much slower growing like maybe 6-12 inches per year in trunk height. Could be wrong with this one though.

[cittic10]

Next time skip the miracle die soil. There's no need to ammend clay soil for crapemyrtles and I'd actually remove that now contaminated soil if possible and replace with the native soil.

[TXboomerang]

I'm kinda baffled with trying to find good info on crape myrtles as far as height/size goes. Texas A&M horticulture dept list the Centennial Spirit as reaching 8-12. Univ of Georgia lists it as reaching 10-20 feet. Reputable tree farms in the area also vary, some say 10-12 feet, some say 15-20 feet. The tag that was on it at Lowe's list it as reaching 12 feet. I would assume that it would grow faster from its current height if it has the potential to reach the 15+ range, and not as fast if it is going to max out closer to 10. I'm just surprised at the amount of conflicting info coming from places with good reputations.

As for amending the soil, I've always read that by combining the native soil with compost or garden soil, you give the tree roots a mixture to grow into before they reach the native soil. Basically, if the container the tree comes in is all nutrient rich fast draining soil, and you drop it into an area of seriously thick and heavy clay, the roots do not move into the clay as well, so blending in some compost and garden soil with the clay creates a "transition" soil. I have some dwarf crape myrtles in the front yard that I planted the same way and they have done terrific. The mixture I make is around 3/4 native soil/clay and the rest compost or garden soil for trees/shrubs, so its not very much non native

[Butterfly4u]

TX boomerang,
Crape myrtle trees unless they are a dwarf variety, (which could grow to 10 ft), will get
tall depending on the growing conditions. They are trees in climates that are warm.
I am going to guess you live in a warm climate, so your trees will or could get big.
The reason you aren't suppose to amend the soil for a tree is,
The tree roots won't want to grow outside of the amended area.
They will stay where the nice soil is, nice delicious composted poo, nice
moist garden soil with Miracle Grow in the soil, and stay within the
amended area virtually until it blows over on a windy day because the roots
can't support the top weight.
Good Luck with your myrtles.

[TXboomerang]

I have never heard to not amend the soil at all. Some of the longtime gardening experts I've talked to in the area say to do it, just don't put a lot of amendment which is why I left about 3/4 native to about 1/4 amendment.
I am having a hard time understanding why the roots would not grow out of that into the native soil beyond the transition mix. If you did nothing to amend the soil, why would the roots grow out of nice nutrient rich soil mix in the container they are growing in and directly into clay, but they won't grow from the slightly amended mix into the clay?
I am basically going on the recommendation of people who have been doing gardens and trees in the Dallas/Fort Worth area for decades, and that is what more than one has told me.

[cittic10]

What butterfly4u said. It can promote girdled roots.
Plus, in clay soil it creates a bathtub effect where water sits in the planting hole rather than drain out.
That said, 1/4 would not a big deal at all had it been any other type of soil but if there is fertilizer in the soil (which Miracle Die soil often does), that could potentially damage the roots. As for people gardening in your area for decades... it certainly is a decades-old practice but as cultural practices change as studies and findings are published, you can either change your practices or continue doing what you've always done. Too many people do the latter.

As for your original question, which I neglected to answer, the newer cultivars often have conflicting growth rates posted online because people just don't really know. It takes decades to get a consensus on these things. The first 2-3 years (dep. on size) are going to be spent growing mostly underground, getting established.