Best tree to provide dappled shade for raised bed garden

So our summers are hot. Almost nothing likes all day sun here. We are looking at low 90's to high 80's until October and this is a mild summer. The west side of the garden is shaded in the afternoon by two native oak trees. I'm hoping to add a couple more deciduous trees around/in the garden to help with the summers. I would love a tree that is useful in some way, either edible or medicinal but it's not totally required. I was thinking about adding a mulberry to one corner but would love others to chime in on whether this is a good idea. I am fencing in my back garden, think food forest/orchard/ botanical garden and adding some annuals next year, maybe that would suffice but I don't know. Ideas? Comments?

My mulberries cast a dense shade and I feel like they extract a lot of fertility around their root zones.  Maybe if you kept them pruned to thin them out.  The leaves from prunings make excellent fodder if you have livestock.

The dense shade was precisely my concern but having it so close in to my house I thought that I could spend more time pruning it than I do other trees. I try to balance my work load, some things I'm willing to expend more time on than others. And it's a large tree that could shade a fair portion of my garden so it might be worth it. Thanks for your input.

I find mulberry (modus alba) very dense, dark shade. If it is a mature tree you can grow a garden at the edge of drip line, but not much of anything really under the branches.

You could maybe pollard a tree to keep it a manageable size.

Locust is good for dappled shade.

Mk nailed it. You can't beat locust for dappled shade and the trees are beautiful. I've grown a lot of thornless honey locust trees from seed. They are easy to grow, grow quickly, and the bees love them. Bees love black locust as well, and they smell wonderful, but the thorns are pretty bad.

Mulberry takes very well to pollarding, but the locust fixes nitrogen  and has dappled shade.
I have both as volunteers within feet of each other, each were cut back to the ground this spring, both are back with a vengeance.
Locust will probably create a lot of volunteer seedlings.
Mimosa casts very dappled shade as well, I have some of them in the same area.
They are less robust.

In making a choice you may want to consider a type of tree the birds are LESS attracted to sitting in, as they will be hanging out above your lettuce, broccoli ... and pooping on them. I love having the birds in and near my food gardens, but not roosting above them. It seems mulberry would have birds hanging out for the berries, and most locust for the thorns (good safety from predators for birds).  Honey locust is thornless, it seems.

Barbara Kochan wrote:Honey locust is thornless, it seems.

Honey locust in it's "natural" state has huge, terrible thorns, but they have been cultivated for years to be thornless.  I grow all mine from the seeds of thornless trees, but still get a thorny one on occasion.  I have a really beautiful one right now that is 10' or so that I grew from seed that has thorns.  It's such a healthy tree, I haven't been able to bring myself to remove it, so I may have one thorny one.

William Bronson wrote:
Mimosa casts very dappled shade as well, I have some of them in the same area.
They are less robust.

Yes, what William said! Mimosas are lovely little trees!  They don’t really grow where I live now, but we had a volunteer mimosa back in DC. Such beautiful flowers!

My favorite fast growing dappled shade specimen that offers, modifiable density for different times of year (light or dense), edible leaves, edible fruit, attracts pollinators, provides living rope-like material for supporting tomatoes, beans and cucumbers, produces compostable green material, seems to distract and repress harmful insects, has non-invasive roots, and can be used to make everything from baskets to wreaths to pleasing beverages, isn’t a tree.
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It’s grapes.

Okay, so it seems like a thornless honey locust seems like my best bet. I'll have to look into where I can get one in this area.

Amy - I'm looking for something to shade overhead. Grapes wouldn't work for this area that way without building a structure. The fencing around the garden is already covered with shade cloth. There was grapes on it when I got here but they died because of the heat, pests and ground squirrels ruining the roots. I do plan on having grapes on the fencing in some of my food forest area.

The garden is on the south side of the house and the house is white aluminum siding which shines even more sun onto it but changing the color of the wall would only heat the house more. It's a conundrum.

Stacy Witscher wrote:Okay, so it seems like a thornless honey locust seems like my best bet. I'll have to look into where I can get one in this area.

Amy - I'm looking for something to shade overhead. Grapes wouldn't work for this area that way without building a structure. The fencing around the garden is already covered with shade cloth. There was grapes on it when I got here but they died because of the heat, pests and ground squirrels ruining the roots. I do plan on having grapes on the fencing in some of my food forest area.

The garden is on the south side of the house and the house is white aluminum siding which shines even more sun onto it but changing the color of the wall would only heat the house more. It's a conundrum.

You may want to buy a tree to save a couple years, but if you aren't in a hurry, they are easy to grow from seed.  I can send you some if you like.

I have a brick wall on the west of my house.
It's right next to a driveway, with no room to plant a tree, so I ran a cable across it and grew a grape vine along that.
It does a good job offering shade and biomass,  not so good at giving me grapes.

Wire rope with plus a ratchet strap, or just a ratchet strap for shorter distances are very easy ways to create a support between two points.

I do have grape vines growing with tomatoes, cucumbers, and butternut squash, but I consider it competition not support.

William wrote:

I do have grape vines growing with tomatoes, cucumbers, and butternut squash, but I consider it competition not support.

Yes, the grape vines wrap around the tomatoes, cucumbers and squash. Use these entanglements to advantage by cutting the long runners so they'll die in place. Using the detached but tangled runner, wrap the free end (proximal) around the living grape plant or your guy-wire to secure sprawling veg. The vine will exfoliate and harden into a useful free-form veg support.

Just a thought here...

If you want dappled (or even controlled) shade, could you do a nitrogen fixing espalier cleverly oriented with respect to the bed?

I don't know if you can espalier goumi, or seaberry, or other nitrogen fixing low-trees, but if there was a good candidate it could be an interesting, maybe medium-high maintenance solution.

Here are some photos to make my issues clearer.

Hi Stacy. Thank you for posting the photos. Your hard work shows in this stunning landscape. I have no helpful tree idea but you did ask for “Ideas? Comments?” in your original post so here it goes.

Focusing on the photo, “bed of dark green zucchini suffering at 7:00 pm” a few things that give me pause. First, the new leaves on your squash plants growing on top - in the most sun exposure - are greener and have fewer yellow spots on them than the large leaves under them. The marigold shaded by the zucchini is also struggling. Is it possible that these plants, which thrive in fields exposed to extreme sun, could be suffering from a nutrient deficiency in the raised bed soil mix that weakened them, making the plants susceptible to a fungus or mildew?

The dappled shade idea via a tree would take years to confirm the hypothesis that the plants suffer from too much light and heat. An experiment using temporary shade cloth could help confirm this hypothesis. But what if the problem is nutrient deficiency and/or disease? Getting a soil test from the county extension service and a shade cloth experiment could confirm the actual cause of the problem. If it were me, I’d contact https://extension.oregonstate.edu/gardening/soil-compost/how-do-i-test-my-garden-soil and take samples or send photos of the squash leaves to the local office near you. Maybe this could save lots of effort in the long run.

Thanks for listening Stacy. I learned a lot from studying this thread!

Not sure if these suggestions are the "best" but I have an interest in getting some poplar trees going at my new place after seeing a neighbor essentially stick a twig in the ground and in less than 6 years had a tree taller than his house. They seem to grow rather vertical than outward, but planting multiple trees in an area could therefore give you the shade/light windows over the course of the day that may benefit the blistering garden plants.

Another would be some kind of maple, as they are nice to tap for syrup and seem pretty resilient and fast growing as well. Most maples seem to spread out nicely for shade and might be too thick but they handle extreme pruning well from what I have been witness to.

Amy - you are probably right about a fungus. I am primarily watering with sprinklers this year as the garden is too large for me to hand water. I know that cucurbits generally don't like this. I may have to switch to drip irrigation next year, but it's so fussy. My other option is to add corn to all beds that have cucurbits as they seem to like that shade. I have some of that damage on my tomatoes as well but they seem to be overcoming it.

Trace - I would love some seeds. I will send you my address via PM.