Large African Acacias

[ahosey01]

Anybody growing any of these and want to share any of their experiences?

There is a massive Senegalia galpinii by the HEB Plus in Brownsville... trunk is easily 4ft diameter.

I am growing Vachellia robusta, Senegalia galpinii, and Senegalia burkei, presently.  Hoping to acquire some seeds from Vachellia permixta, Vachellia kirkii and Senegalia ataxacantha later this year also.

Anyone else doing this?

[Than]

Do you grow them in pots or in the ground? Any photos?

I only have a Vachelia tortilis in a pot. It is only one year old and I keep it indoors for the winter. It is difficult to find any info online about their care as there isn't much interest in growing them outside of their native range I believe. My guess is that it cannot take frost, but I will put it in the ground this spring and see what happens. I just love their iconic umbrella shape. They would also make perfect canopy for other plants below.

Oh, and it's a magnet for mealybugs.

[ahosey01]

5 hours ago, Than said:

Do you grow them in pots or in the ground? Any photos?

I only have a Vachelia tortilis in a pot. It is only one year old and I keep it indoors for the winter. It is difficult to find any info online about their care as there isn't much interest in growing them outside of their native range I believe. My guess is that it cannot take frost, but I will put it in the ground this spring and see what happens. I just love their iconic umbrella shape. They would also make perfect canopy for other plants below.

Oh, and it's a magnet for mealybugs.

Mine are in the ground currently.  I have a fairly small garden, but by planting comparably sized trees with comparable growth rates fairly close together, you simulate the scrubby growth habit of the bush environment.  Some of these are maybe 10ft apart.  No photos yet but I'll take some later in the growing season once things have put on some size.

The guy that started Arid Zone Trees (they are since out of business) had a beautiful demonstration garden where they collected tons of info.  They said that they trialed Vachellia tortilis and it was hardy to at least 18F:

Kevin's Initial Project

There are also two growing at U of A in Tucson, and they had a prettty big freeze in 2011 that knocked a bunch of stuff back.  You could probably check their map and street view the damage if there was a photo from back then:

Find Trees & Learn | University of Arizona Campus Arboretum

I would like to try species this also, but I think where we are the soil is probably too heavy.  I generally have to grow stuff found on clays near rivers.

[ahosey01]

5 hours ago, Than said:

Do you grow them in pots or in the ground? Any photos?

I only have a Vachelia tortilis in a pot. It is only one year old and I keep it indoors for the winter. It is difficult to find any info online about their care as there isn't much interest in growing them outside of their native range I believe. My guess is that it cannot take frost, but I will put it in the ground this spring and see what happens. I just love their iconic umbrella shape. They would also make perfect canopy for other plants below.

Oh, and it's a magnet for mealybugs.

Here is an absolutely monster Senegalia galpinii at a house by where I live.  Buddy of mine believes it was planted in the 80s or early 90s, which would make it 35-45 years old.  Trunk is at least 4 feet across, maybe more.  Look how it's planted directly over the water main feeding into the house, lol!

Old Creek Ln - Google Maps

[Than]

35 minutes ago, ahosey01 said:

Mine are in the ground currently.  I have a fairly small garden, but by planting comparably sized trees with comparable growth rates fairly close together, you simulate the scrubby growth habit of the bush environment.  Some of these are maybe 10ft apart.  No photos yet but I'll take some later in the growing season once things have put on some size.

The guy that started Arid Zone Trees (they are since out of business) had a beautiful demonstration garden where they collected tons of info.  They said that they trialed Vachellia tortilis and it was hardy to at least 18F:

Kevin's Initial Project

There are also two growing at U of A in Tucson, and they had a prettty big freeze in 2011 that knocked a bunch of stuff back.  You could probably check their map and street view the damage if there was a photo from back then:

Find Trees & Learn | University of Arizona Campus Arboretum

I would like to try species this also, but I think where we are the soil is probably too heavy.  I generally have to grow stuff found on clays near rivers.

18F? Incredible for an African species. My lowest is usually 28F. Then again I guess it gets cold in the Sahara at nights. You gave me hope it may make it in my garden. If the mealybugs finally p!ss off

[ahosey01]

4 hours ago, Than said:

18F? Incredible for an African species. My lowest is usually 28F. Then again I guess it gets cold in the Sahara at nights. You gave me hope it may make it in my garden. If the mealybugs finally p!ss off

I think you'd be surprised.  A lot of these things are native to the highlands in East Africa.  While they don't typically experience significant freezes in habitat in the current climate (though some can depending on altitude) I don't feel like it would be hard to imagine a time in the ice age 15k years ago or so when those areas got fairly cold. 

The capital city of Ethiopia - Addis Ababa - for example, has experience a freeze in 6 separate months and has dropped into the 30s in all months but 3.  There are some pretty significant elevation impacts in that part of the world.

[Than]

Not sure if the climate 15k years ago still affects the hardiness of plants nowadays. Perhaps their DNA has forgotten the tough times.

Are there Vachelia tortilis in Addis Ababa?

[ahosey01]

15 minutes ago, Than said:

Not sure if the climate 15k years ago still affects the hardiness of plants nowadays. Perhaps their DNA has forgotten the tough times.

Are there Vachelia tortilis in Addis Ababa?

iNat shows a couple in the immediate vicinity:

[richtrav]

Tortilis and erioloba should be the hardiest, whether or not they can take a humid climate I’m not sure. Xanthophloea, galpinii, kirkii and robusta certainly can but xanthophloea and hard freezes don’t go well together.

The former DELEP program at the U of A would be a good starting point, they have some notes on freezes in Tucson and Yuma from 2007 here. It includes many African acacias:

https://cales.arizona.edu/desertlegumeprogram/sites/cals.arizona.edu.desertlegumeprogram/files/aridus19-1.pdf

And a lesser freeze in 2003 here:

https://cales.arizona.edu/desertlegumeprogram/sites/cals.arizona.edu.desertlegumeprogram/files/aridus16-2.pdf

Their Yuma field was leveled around 2010, but there is a good summary of what all they grew here, including how things tolerated the 2007 freeze:

https://repository.arizona.edu/handle/10150/622003

(Just click on download to see it, it’s about 83 mb)

There is also an article on how legumes in Tucson fared in the 2011 freeze:

https://repository.arizona.edu/handle/10150/556785

[ahosey01]

5 hours ago, richtrav said:

Tortilis and erioloba should be the hardiest, whether or not they can take a humid climate I’m not sure. Xanthophloea, galpinii, kirkii and robusta certainly can but xanthophloea and hard freezes don’t go well together.

The former DELEP program at the U of A would be a good starting point, they have some notes on freezes in Tucson and Yuma from 2007 here. It includes many African acacias:

https://cales.arizona.edu/desertlegumeprogram/sites/cals.arizona.edu.desertlegumeprogram/files/aridus19-1.pdf

And a lesser freeze in 2003 here:

https://cales.arizona.edu/desertlegumeprogram/sites/cals.arizona.edu.desertlegumeprogram/files/aridus16-2.pdf

Their Yuma field was leveled around 2010, but there is a good summary of what all they grew here, including how things tolerated the 2007 freeze:

https://repository.arizona.edu/handle/10150/622003

(Just click on download to see it, it’s about 83 mb)

There is also an article on how legumes in Tucson fared in the 2011 freeze:

https://repository.arizona.edu/handle/10150/556785

I had that 2007 article already but I couldn't find the 2011 after I'd read it some years ago.  DELEP's site is kind of hard to navigate.

Big surprise to me that Vachellia kirkii took less damage in that freeze than Senegalia galpinii.  The one by the HEB doesn't even have any dead wood of that size described in the article that I can see in the canopy from '21.

[Than]

I just read this article on The Guardian about a tree failing to grow because the symbiotic bacteria it needed were not found in the soil. That made me wonder if this could be a reason for trees like Acacias or Fabaceae in general to fail when we try to grow them far away from their native regions.. 

[ahosey01]

8 hours ago, Than said:

I just read this article on The Guardian about a tree failing to grow because the symbiotic bacteria it needed were not found in the soil. That made me wonder if this could be a reason for trees like Acacias or Fabaceae in general to fail when we try to grow them far away from their native regions.. 

The subject matter here makes sense - but I also am at least somewhat confused regarding your point.  Are you saying that Fabacae generally struggles outside of its native range?

I can think of no broader family of landscape plants than Fabacae that succeed in so many highly varied climates well outside of their native ranges.  In fact, I can't think of a woody tree with a more pantropical range than Vachellia farnesiana.  Vachellia seyal grows all over the African subtropics, tropical highlands and even the Arabian peninsula. There are definitely examples where this isn't true - for example, Australian woody tree species tend to do poorly in South Texas for whatever reason.  But there are plenty of examples where this is true - a huge range of woody material at the DELEP fields in Arizona for decades.

[Than]

2 hours ago, ahosey01 said:

The subject matter here makes sense - but I also am at least somewhat confused regarding your point.  Are you saying that Fabacae generally struggles outside of its native range?

I can think of no broader family of landscape plants than Fabacae that succeed in so many highly varied climates well outside of their native ranges.  In fact, I can't think of a woody tree with a more pantropical range than Vachellia farnesiana.  Vachellia seyal grows all over the African subtropics, tropical highlands and even the Arabian peninsula. There are definitely examples where this isn't true - for example, Australian woody tree species tend to do poorly in South Texas for whatever reason.  But there are plenty of examples where this is true - a huge range of woody material at the DELEP fields in Arizona for decades.

No, of course I am not saying that. Many Acacias and other Fabaceae in general are grown all over the world. Many Australian Acacias thrive here for instance.

However, I am wondering if in some, rare, cases an exotic tree somewhere in the world, in someone's garden, failed due to this reason. 

[ahosey01]

49 minutes ago, Than said:

No, of course I am not saying that. Many Acacias and other Fabaceae in general are grown all over the world. Many Australian Acacias thrive here for instance.

However, I am wondering if in some, rare, cases an exotic tree somewhere in the world, in someone's garden, failed due to this reason. 

Oh that makes a lot more sense.  There are probably a ton of things like that.

I have no idea how we would know for sure lol but it seems super reasonable.

[hbernstein]

A word of warning: If you happen to grow them to maturity, I would be extremely watchful regarding seedlings in the landscape and their ability to spread. Several species are or have the potential to be invasives in Florida. I have no doubt that the same might apply to Texas.