Hi Eddie,

The relatively fast drainage of sandy soil might be somewhat comparable in drying time to the well-drained gritty soils of our western counties, where this species occurs naturally in the state. Still, sandy soil can sometimes have proportionately little organic matter in it, which helps to retain moisture and nutrients, so amending it with a bit of compost can help in that regard. (It won't need much...maybe a shovel-full per plant of this size.) When new plants decline quickly, though, it's usually related to root health in the sense of either poor root condition upon purchase, poor planting approach (not loosening roots well if tangled in the container or not planting at the proper depth), or over- or under-watering after planting. Feeling the soil a few inches deep next to or within the root ball is the best way to judge when watering is needed. For plants like this that prefer moist but well-drained soil, the soil should be somewhat dry to the touch at that depth (at least a full finger's worth) before watering is needed again. Water thoroughly at each occasion it's needed so you make sure the moisture reaches the deeper layers of soil.

We can't tell from the photos if planting depth is a factor here. The root flare, which is the point where roots begin to branch off of the trunk base, should sit just at the soil surface so they're neither exposed too greatly nor buried under several inches of soil or mulch. Granted, on plants this young, the root flare might not be very "flared" or prominent, but if enough soil is gently removed from the root ball prior to planting, it can be located. It's not uncommon for nursery-grown plants to be buried too deeply in their pots, with the root flare situated a couple inches down from the surface.

The bronze-toned color of the foliage can be quite normal for many varieties of Arborvitae in winter, especially when young or stressed. 'Emerald Green' may have been named for its tendency to stay greener in winter, but we've seen them develop some bronzing too, largely dependent on site conditions and weather. Although a paling of color or browning during the growing season often indicates a dying plant that can't be salvaged, this type of darker bronzing might not necessarily mean the plants are going to fail. We've seen some young arborvitae turn nearly chocolate-brown in winter and still be just fine come spring, a trait they grow out of as they mature and get roots established in the ground.

Since you planted them as recently as this past summer, they will still need several months or more to establish, and it's not uncommon to see little above-ground growth during this phase since newly-planted plants put lots of energy into root growth before they can resume leaf/branch growth to any great extent. Plus, many trees and shrubs have finished their active above-ground growth by midsummer since they need a surprising amount of time to prepare tissues internally for winter. Foliage and stem growth put on too late in the season, spurred either by trimming or late fertilization, can be too tender to survive winter, so it's good that this doesn't appear to be the case here.

If you do opt to replace the plants, wait until spring to acquire and replant them. Whether you start fresh or keep these, over the long term, you may wish to remove the landscape fabric entirely, so as the Arborvitae grow and their roots reach well beyond their trunks, the landscape fabric doesn't interfere with moisture, nutrients, and oxygen reaching the soil below it where the roots will primarily be growing.

Miri

Hello Miri!

Thank you for your detailed responses!!

I removed the landscape fabric and put "real" mulch around all the plants so hopefully that helps. Fast Growing Tree's is going to send me new trees Mid-April. Do you think this is too early to decide if the ones that have already been planted will survive?

Thanks!

Eddie

Mid-April is probably sufficient as far as determining if it looks like the current plants are going to pull through or not. While evergreens can be notoriously slow sometimes to manifest symptoms of root death or other stresses, the weather will probably be mild enough for healthy plants to have resumed growth (or at least greened-up from any winter bronzing) by that point.

Miri

You're welcome!

Hello Miri,

Most of the Emerald Green Arborvitae's I showed above seem to be doing better, but some are turning partially and fully brown. Are they dead? If not, is there anything I can do to prevent them from dying?

I currently have 1 gal/hr drippers for each tree that I run for 1 hours 1 time per week, which seems to enable me to stick a screwdriver in 6" down next to the base of the tree when it's complete.

Thanks!

Eddie

Hi Eddie,

The completely-brown Arborvitae are unfortunately dead and cannot recover. The brown growth on still-green individuals is also dead and can be carefully trimmed off it they do not have green branch tips. (Or they will eventually fall off on their own, but that can make it harder to see if it's progressing.) We can't determine what caused the dieback, but usually it's related to root health when young plants are still establishing. Over- and under-watering are common causes, as is not adequately loosening a root ball upon planting, if it was tangled or the plant root-bound.

Arborvitae, like most conifers, are sensitive about soil moisture level and drainage; they will not tolerate poor drainage or being over-watered, though drought can also lead to leaf damage. Drip irrigation is a great way to deliver water to the roots without wetting foliage, and is great for letting water slowly seep into the root zone, but if applied on a set schedule without testing the soil first, might still over- or under-water plants. Feel the soil about four to six inches deep to determine when watering is needed, plus to see how far down an irrigation session really reached. If damp to the touch at that depth, watering is probably not needed (or if done after watering, you can assume the amount of water applied was sufficient). If somewhat dry to the touch at that depth, then watering will probably benefit the plant (and if done after watering, that tells you a longer duration may be needed so it soaks in far enough). Using a screwdriver can help, but if you're just judging by ease of inserting the tool and not how wet or dry the soil is at that depth, it might be giving misleading results.

If this is not a result of excessive or deficient soil moisture, perhaps the plants had poor root health/development at the outset, but we can't tell at this point. All you can do is to give them time and replace those that have succumbed. If you look at the roots after removal, one sign associated with root rot is how the roots pull apart: if tugged and the outer sheath is mushy or pulls off easily from the stringy inner core, that suggests they were infected by one of the several "root rot" pathogens, which take advantage of roots not able to access enough oxygen from overly-wet soil. If dead roots snap in two instead when tugged, and take more force to break, then root rot is less likely and either they got too dry instead or something else affected them.

Miri

Hello Miri!

That's a bummer to hear that the one tree is dead :(. I'll wait until next spring to take it out and replace it. I assume I can still check for root rot then?

And I've removed all branches that have no green on them, trimming them back all the way to the main branch. I left any branches that had any green left on them (tho I assume I'll need to remove those soon too).

As usual, thanks for the advice! Much appreciated!!

V/r,

Eddie

Hello Eddie.
With time it will become clear which are going to survive and which you will need to replace, but you don't have to pull them now.
Our tree planting and watering information is very helpful  to help establish new trees, and are worth reading through for clues. 
Tree planting: 
https://extension.umd.edu/resource/planting-tree-or-shrub

Monitoring and watering when needed is essential for the entire first 24 months of establishment, but it's best to manually make sure the water is getting where you think it is, not by just using a screwdriver but your finger to gauge that the soil is cool and moist around the root area. This page will explain more: 
https://extension.umd.edu/resource/watering-trees-and-shrubs

One more thought.... Emerald Green Arborvitae are widely (and relatively inexpensively) available locally at nurseries, hardware, and big box stores. You might get a better, less stressed plant in a bigger pot closer to home.


Christine

Sorry, I do have another question with regards to the watering page you linked. In it, it says the following:

Focus watering near the drip line of your plant’s canopy where feeder roots are located. Applying water just around the base of a trunk does little good and can lead to decay.

As you can see from my photos, I am using a drip irrigation system, with one drip nozzle at the base of each tree. Do I need to buy several drippers for each tree and distribute them within the drip line (which is currently very small because the tree's drip lines are only like 1 foot in diameter)?

Thanks!

Eddie

No, we think with trees that small you are fine with the one nozzle. Use the screwdriver and your finger on both sides of the plants after the next watering to see that they are all cool and moist. Keep watering right up until the ground freezes for winter.


Christine

Ok thanks! And I assume once they are older, they'll no longer need to be irrigated, so there would still be no need to spread more drippers around under the drip line?

Thanks!

They will be more self-sufficient when older, though any plant, established or not, would need periodic monitoring for watering needs during drought so it's not injured or stressed.

Miri

Oh ok. I guess I just assumed because I never see anyone watering large trees, like those in forests, that they just don't need watering because they are more tolerant but I guess every tree has it's water needs!

Thanks for the reply Miri!!

V/r,

Eddie

Forest soil is quite different than the soil left behind on the yard after home/neighborhood construction. Topsoil tends to be removed during construction and might not have been replaced, and the equipment itself plus frequent foot traffic compacts the soil. Compacted soil and soils low in organic matter (topsoil holds the most organic matter in natural soil layers) have a harder time absorbing water when they've gotten too dry, have a harder time shedding excess water when overly wet, and have reduced oxygen content for root health because the pore spaces between soil particles are smaller. This is one reason why it's beneficial to use an organic mulch or compost/topsoil topdressing on planting beds -- so the soil is gradually amended with organic matter as the mulch breaks down in order to help replace what was lost and to help alleviate some compaction. Wild forest trees definitely can get drought stressed (and if too severe beyond their tolerances, or overlapping with too many other ailments, they die), but since we don't want to leave our home landscape trees' survival up to fate like that, we water them when the weather hasn't been wet enough. And you are correct, different tree species do have different preferences for how moist or dry their roots get, just as they have different tolerances for how excessively wet or dry conditions they can survive. Arborvitae prefers middle-of-the-road conditions: somewhat evenly-moist soil that is neither too dry nor soggy or poorly-drained.

Miri

Ahhh ok, that makes sense!

Thanks for the additional info Miri! Much appreciated!!

You're welcome.