Understory plants for Dallas/Fort Worth zone 8 (nitrogen fixing preferred)

Hi all,

I'm looking for ideas for chop and drop and ground cover species for DFW.  We're in zone 8 but we have very hot and dry summers.  

Some ideas I've had so far
- goumi berry
- clover as a potential ground cover
- mimosa
- was going to try longevity spinach as a ground cover but its not consistently perennial
- I have a hill on one side of my house and would like to use clumping grass like muhli to retain water and sediment, but also as a chop and drop - are there better clumping grass species for this use?
- have tried comfrey but it struggles in summer
-mimosa tree was an idea as well for chop and drop but i wasn't sure about how well it does with heavy pruning

Any and all ideas welcomed!

Thanks

Dave, what kind of soil do you have?  (to others - DFW is a soil transition zone, and there are several distinct types in the metro area). I'm now in the cross timbers, but until 2013 I was in the black gumbo.

I have lots of kinds of improved elaeagnus - autumn olive, goumi, silverberry, etc.   These grow well, but don't fruit well as understory (for me).  I highly recommend "hybrid silverberry".  I ordered mine from One Green World, but I do rarely see (smell!) them growing around DFW.  They smell heavenly when they bloom in Nov/Dec, and are one of the rare bee foods blooming at that time.   I guess you could chop it, but I just prune slightly as a specimen.  It is in the sun, but right next to an nectarine tree.

One of my most prolific mulch understory plants are the bird-planted Cherry Laurel (aka Laurel Cherry) trees.  These are evergreen, beautiful year round, birds love them, bees will eat the blooms, and you can probably cut them every two weeks.  The leaves are waxy and don't break down quickly as mulch.  The neighbors think they are weeds.

I let the mimosa stay now, mostly to atone for the sins of my youth trying to eradicate them.  The blooms are good bee food and herbal medicine.  However, small ones (understory) recover from cutting very slowly.   In a large, sunny area, if you let it get huge and multi-year established, then it can work.  I have two in the front that I pollard back to 4' stumps about twice a year, and I get a lot of 10-15' woody/leafy switches that I carry to the back.  The neighbors say they are weeds and damage your foundation.  

For ground cover, I let the lawn weeds grow wild in spring and fall, but they refuse to grow in the summer:  chickweed, henbit, yarrow, narrow leaf plantain, wood violets, etc.  Also Lemon Balm (Melissa) is exuberant and seems to improve the soil.   If you can get clover to establish, then it will mix with those--I can only get patches in places they choose for themselves.  

Russian comfrey does great for me, if I irrigate it.  If you are growing other things that require irrigation, then the comfrey is a great indicator of when to water.   When it is wilted flat, you water everything deeply and watch it recover.  If you don't want to irrigate, then I've only seen (other people have) success with wood chips.  

Lots of things don't grow as well here as expected--I may have persistent herbicides or something.  If I think of anything else, I'll post again.  

Please let us know what you try and how it works out!

Kerry, fantastic info and ideas, thank you. My soil is HEAVY clay. It's not black gumbo, but is a clay loaded with limestone rocks.  I use a heavy wood chip mulch to attempt to improve the soil however,I want to introduce some support species in between the trees where there's space.

I'm browsing one green world now and this site is awesome, thanks for the tip. Looks like they are currently out of the hybrid silverberry so I set a reminder for when it comes back in stock. In the interim im going to order some of the varieties you mentioned.

Good info on cherry Laurel and especially mimosa. I've never grown the mimosa before so it's good to understand it's growth habit.

Good ideas on ground covers as well. I currently have some of the plants you've mentioned such as yarrow and lemon balm in other parts of my landscape in an ornamental context, so I think I'll split these in the next week or two and plant out in the food Forest.  

Also, good to know you're having success with the comfrey.  I bought cuttings of one of the bocking varieties online and still have a couple plants alive but they didn't seem to like the heat last year, maybe this year will be different.

Thanks again for your post, you've given me some good options to think about.

Dave

Poke Phytolacca americana  if it is happy can produce large amounts of soft leaves for mulch.  Prefers edge or bright shade.  Our best plant grows next to the north side of our house, beneath trees, so gets quite a bit of shade, and no irrigation.

I have always been a firm believing that 80% of a new food forest should be nitrogen fixer and at least 20% at maturity. So with that in mind I am going to recommend some nitrogen fixers.

Dalea candida (my top pick)
Scotch Broom/Cytisus scoparius
Acacia cyclops
Acacia longifolia
Acacia melanoxylon
Kudzu/Pueraria lobata (its invasive, I don't recommend planting it, but you could)
Astragalus cicer
Medicago sativa
Trifolium hybridum
Trifolium repens

http://www.perennialsolutions.org/?s=nitrogen+fixer

Calliandra would be worth a shot.

I'm a little south of DFW, but generally have the same temp range as the metroplex. Here are some things I've grown:
Mimosas take very well to heavy pruning once they get going, and have plenty of light.
Pride of Barbados/Mexican Bird of Paradise is another legume that stays a shrub. They do well with high heat and low water.
Rattlebox is a large shrub/small tree that is quite vigorous, though it likes a bit more water.
Partridge pea is an herbaceous annual legume which produces lots of biomass and can survive total neglect.
I'm growing alfalfa as a ground cover in my garden paths, and it's been pretty durable since it's gotten established.
I have a type of Senna, not sure what species, that grows well.
Those are all legumes, so I assume they'd fix nitrogen. I've never had the opportunity to grow any Elaeagnus species, but it's on my list to try.

Non legumes I've had success with include:
Nandina for biomass/mulch
Althea/Rose of Sharon
Hardy Hibiscus
Beautyberry
Chrysanthemum
Texas Mountain Laurel
Dwarf Barbados cherry
Mexican mint marigold
Butterfly weed (likes some sun)
Cannas & elephant ears

I grow a lot of ornamental plants for market, and typically germinate/propagate more than I sell, so I often stick the extras in open spots in the forest garden. Then I can use them for mulch or for pollinators.

Apologies for the late reply all, I thought I was receiving notifications on replys but apparently I'm not.

This is a fantastic list. Exactly what I was looking for. Bengi, thanks for the nitrogen fixing options as well.  I'm going to start exploring these species online to see where I can purchase some of them. I find that the nurseries in my area really have plant varieties other than the staples so I'll probably have to order seeds, cuttings, or plants online

Glycyrrhiza glabra ~ Licorice