High heat and shade strategies

[Pigskin Pete]

Temps hit 95⁰ here in my lovely patch of home in zone 8a. We get high heat, dry wind, and intense sun. Without exaggeration, I'd say our "springtime" showers and light temps will be gone very soon. Not uncommon to have 20+ days in a row of 100⁰ heat.

I bought a shade screen from a local hardware store, your typical black mesh screen. I have one of two quick options.

Keep the garden in the middle of my yard. I can set up the screen so it will get direct sunlight from basically daybreak until about noon and then shaded light thereafter until about 7 pm when the roof blocks the sun and even more shade settles on the garden. Advantage - more light. Con - more heat exposure.

I can also forgo the shade and move the garden closer to the Eastside wall of the house so that it gets direct sunlight from daybreak until noon and then shade from the roof/house for the remainder of the day. Advantage - less heat exposure. Con - less sun.

I suppose my questions are both specific and general. Specifically, which of these two options sounds better? And generally, what do yall do to balance light requirements and high heat exposure to get through those rough summers? The heat and sunlight here are exceptionally brutal. Shade, water, and wet cloths around my pots are the plan so far. I am primarily stewarding junipers, boxwoods, crapes, and bald cypresses. I do have a few other species but everything in my collection is hardy to my zone, in theory at least.

I don't think water maintenance alone will protect my trees. Last summer I lost a few and I'm certain the heat was a heavily contributing factor.

 

[Shibui]

We don't get quite the same run of hot days down here but plenty of days over 100E through summer.
I get by with a range of different measures -

• Shade - only the more delicate species get shade here. 50% shade cloth over the growing area. Those trees are basically shaded all day every day after hot weather kicks in. Pines, Junipers and most of the Australian natives don't share the shade. They get full sun all day right through summer.
• Water - watering steps up to match the drying which can be a lot more than you think. Trees that have not been repotted recently typically require more watering as the spaces in the soil where water can go is now filled with roots. also, more thorough watering to make sure that water gets right into the roots. When I started I also lost trees through spring and summer. Autopsies revealed that the centre of the root ball was dry. Water had not penetrated right in so each day the trees got drier and drier until they could not survive. Need to make sure water soaks right in. A weekly soak in a tub is good insurance to make sure they get properly wet at least once a week.
• Gravel trays - Smaller pots and sensitive trees are placed on gravel beds - trays filled with gravel and water. Evaporation from the trays helps cool the trees and reduces their need for water. Roots will often come out the pot drain holes and into the water tray to access more water.
• Species - Only grow species that can handle the local conditions.

I don't think there is a recipe for how much light and shade is correct. It's a balance between more sun for compact growth and more shade to reduce water needs. Every place will have a slightly different blend. Luckily your trees will cope with a wide range of shade so it probably pays to err on the conservative side to begin with.
Good luck with finding a balance that works for your trees at your place.

 

[RKatzin]

One thing I would add to that is to be careful to not let the sun hit your pots. Even sun lovers like juniper can get cooked by hot pots. I use boards or rocks or other plants to hide the pots from the sun.

 

[namnhi]

I feel your pain. Having sun up to 12:00 is too long. 10:00 would be better. Am out working on trees and can feel the darn heat after 9:00 AM. The sun feels so much hotter nowadays... I feel most trees will not make it without water twice a day. I used 90% shade cloth. Some people think it is too much but I will be glad I did when the heat start. All this and we only hitting low 90s.
Give your plants as little sun as possible.

 

[IzzyG]

It really depends on the species, tree/pot size and history. Colorado spruce, most junipers, bald cypress, etc. that are healthy and have not had recent work done(restyling, repotting) I’d go with your first option (more sun) especially if they’re bigger trees with bigger pots. Azaleas, engelmann spruce, etc. or have compromised health and are smaller/smaller container will do better with the latter(less sun).

There’s definitely outliers. I know of a Colorado blue spruce that have consistently gotten more shade as it spent most of its life(and was collected), under the shade of larger tree. A large part of it is definitely knowing the individual tree. When in doubt, give it more shade initially and transition to more light. If health drops, you can always go backwards and find the happier medium.

 

[johng]

I would opt for the second scenario...I am from Houston and live in South Carolina now...8b Sun from sunup until noon is gracious plenty where you are and will help you better care for your trees. You can always give them more sun if needed but too much sun and you may experience more problems....Err on the side that is safest for the trees...especially if you are relatively new to this hobby. Learning to care for your trees so that they are healthy and grow vigorously is absolutely essential for being successful in this hobby.

 

[bwaynef]

I think it was @johng that also suggested keeping weeds out of pots will allow the trees to get more water. (Weeds MIGHT keep the soil surface a bit cooler, but at a pretty big expense to the tree's ability to find water.)