Fruit trees under Eucalyptus deglupta rainbow gum? Allelopathic effects?

[happyhana]

There are a couple mature rainbow gums on the property I plan to collect seed from this year to expand the rainbow forest. They are such captivating trees and I must have more!

They produce a beautiful medium shade that would be great for my growing collection of Theobromas and other misc fruit trees that tolerate shade. My concern is whether E. deglupta plays nice with understory trees, specifically cacao and Dalbergia retusa cocobolo.

Hoping someone on here has experience with these combinations, mahalo!

[Finca La Isla]

I’ve seen rainbow eucalyptus used to shade coffe in CR.  It looks good and the shade seems about right.  But I’m not too sure.  There are so many nitrogen fixers that make nice shade and good quality mulch for cacao that I would give the rainbow gum a miss.
Can you imagine Flowering Brownea shading your theobromas?
Peter

[wonderfruit]

I remember that nothing grows well underneath an eucalyptus.

[Mike T]

A bit hard to generalise with Eucalypts as there are 100s of species ranging from less than a metre to over a 100m tall and across all climates. E,deglupta is one of the few outside Australia and get pretty big and lives in wet tropical areas. While many Eucs are allelopathic this doesnt seem to fit the profile of the worst offenders. It doesnt have high oil content and, isnt pyrophyllic. At around 200 ft maximum they can grow into whoppers.

Just outa interest. Imagine the big trees in the Styx Valley in Tasmania where numerous Eucalypts of quite a few different species exceed 200 ft and some E. regnans exceed 300ft. In the 1800s some the tallest trees in the world were in Victoria and while they were measured up to around 375ft maybe bigger ones were felled. These days there are no E.regnans over 330ft.

[happyhana]

Thanks all for the input!

Hearing that coffee is being grown under rainbow gum shade is encouraging. Yes, there’s better companion plants for cacao, this is a case where I’m trying to make useful a strictly aesthetic planting.

I’ve been around a number of eucalypt species and agree, deglupta is different. Lacks the pungent aroma, branches bark and leaves decompose quickly for a gum.

Will report back if I notice comparatively reduced production under the rainbows.

[Finca La Isla]

Have you seen brownea?  The only thing that would be more beautiful would be amherstia nobilis.  Have you seen that?  Really some of the most attractive, attention getting flowers in the world.  And they are better for your soil then eucalyptus.
Peter

[happyhana]

Have you seen brownea?  The only thing that would be more beautiful would be amherstia nobilis.  Have you seen that?  Really some of the most attractive, attention getting flowers in the world.  And they are better for your soil then eucalyptus.
Peter

Ahhhhh, Pride of Burma, stunning tree! Friend of mine has a gorgeous example, plan on taking a few air layers when life slows down a bit. It’s a rare tree here, I’ve only seen one example, not sure about growth rate and ultimate size. Do they provide enough headroom for cupuacu?

Brownea flowers aren’t my favorite, they remind me of the terrible African tulip. What about Delonix regia? I would guess it doesn’t cast enough shade and has aggressive surface roots.

Dalbergia retusa will certainly be in the mix as a nitrogen fixer. One benefit of rainbow gum is that it’s huge size and fast growth will provide a privacy screen of the neighbors.

[Mike T]

I have spread a few Browneas from Jim West around and they look nice alright. A big tree is in a suburb near mine also. There are a gew Pride of Burmas around here also but they never seem to have seeds just the flowers.

[voyager]

They are beautiful trees.
The coloring of their bark makes them eye candy.
I was going to plant some on my property.
Then, I read that they turn invasive very easily.
I already have a number of invasive weed trees, Secropias, Gunpowders, Albizias, and maybe others.
I spend a lot of time and expense chainsawing the weed trees off my property to protect its native trees.
I decided I wouldn't add to my problem with more weed trees.

Do as you see fit.
Even if you don't someone else will.
The islands are filled with invasives.
Controls rely on voluntary compliance, and no one does.

[wonderfruit]

First time I check that Eucalyptus deglupta. You learn something new every day

[happyhana]

They are beautiful trees.
The coloring of their bark makes them eye candy.
I was going to plant some on my property.
Then, I read that they turn invasive very easily.
I already have a number of invasive weed trees, Secropias, Gunpowders, Albizias, and maybe others.
I spend a lot of time and expense chainsawing the weed trees off my property to protect its native trees.
I decided I wouldn't add to my problem with more weed trees.

Do as you see fit.
Even if you don't someone else will.
The islands are filled with invasives.
Controls rely on voluntary compliance, and no one does.

My own observations and reading reveals rainbow gum to be a low risk of becoming invasive in Hawaii. Each year my 2 trees produce copious seed and I’ve yet to spot a single volunteer. In my area rainbow gums are commonly seen as solitary trees.

The Hawaii Pacific Weed Risk Assessment rates it as low risk.
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnx3ZWVkcmlza2Fzc2Vzc21lbnR8Z3g6MjlhMjY1NmRlMDk1NmU5Mw

[happyhana]

I have spread a few Browneas from Jim West around and they look nice alright. A big tree is in a suburb near mine also. There are a gew Pride of Burmas around here also but they never seem to have seeds just the flowers.

Around here Pride of Burma will occasionally set seed, hard to spot as the pods are quite colorful and match the flowers. The pods need to be bagged as the seed is sent flying when they open. I don’t know if seedlings have much variability with regards to the flowers.

[spencerw]

from my research e. deglupta is only allelopathic in a dry-ish environment. when they are receiving plenty of rain they play well with others. as you stated they dont seem to spread like say e. robusta here. maybe the seeds have a hard time germinating or something else. they can get huge though. ive been coppicing mine at about 6' just to watch the trunk grow fatter and get the colors. i cannot allow a tree to get that big especially in the lava soils where there is less than 6 inches of soil!

[happyhana]

Probably too much vegetative shading for seed germination. Read that seeds like surface sow and kept wet in direct sun, like conditions of an exposed river bank.

Coppicing at six feet sounds wild! Must look large an extra large bonsai. Does this encourage buttresses? Think I’ll try this myself.

Interesting that the weed assessment line for allelopathic is blank, no value given. Thanks for your insight on dry conditions.

[spencerw]

ive only cut it twice at that height. so the trunk is only about 6 inches diameter at the cut point. only a few years old, and growing in a forest condition so its not super fast. id like to grow some more but pollard them at 10' to get some posts eventually