Developer completing a new development:

Area 1 Trees around his sign, in a 'park' with a 'running trail' and a 'pond' (The quotes indicate that these are in very preliminary stages.)

The 32 trees around the sign and park went in well. Lots of debris in the soil (rocks, sticks) which made it impossible for me to use my Groundhog.

Area 2 was different. It was the edge of two utility line right of ways where they had put the sewers in. There was NO topsoil. This was the edge of the right of way, so the subsoil was pretty much undisturbed. (The topsoil was likely used to back fill the trench. Isn't that how it usually works?)

The soil was heavy clay, more suited for making bricks. You know the standard perc test for septic fields? This soil had a perc test time of a week. The trees were white spruce, Swedish aspen, hill poplar. The spruce were balled 5' trees, the poplar were in 3 gallon pots.

Digging this stuff was a matter of using a mattock and shattering the top layer, then pulling away great gobs by prying and wrestling with the mattock.

Now all three species tolerate water, but this kind of unfired ceramic pot had me nervous.

The owner had a bobcat with an auger on site. He offered to auger at least the start of a hole, and to bring in some top soil for use around the trees.

I had him create a 3' deep by 1 foot hole (widest drill the bobcat operator had.)

I filled the hole with top soil, lightly packing it every 6 shovel fulls. (Jumped into the hole and bounced around a bit.) I figured what I was doing was effectively creating an inefficient French drain for each tree. The top soil was also heavily clay based, and looked and smelled like it was a ground up beaver pond. Lots of sticks, stones, and a bit of anaerobic smell.

The spruce dirt balls were larger than the 12" hole, so for them, I chipped out a wider hole, setting the spruce tree so it was close to flush with the surrounding land.

The poplars I set with the top of rootball about 4" down, below the surrounding area. In all, I did 17 trees this way.

After setting the trees in I watered each tree with a 5 gallon bucket of water. For most of this first batch there was still standing water in the moat when I was 4 trees down the line.

The owner pointed out to me that the soil in the holes was going to consolidate, dropping the trees several inches, and aspect I hadn't considered.

Once he pointed this out on the next area with similar setup, I left the trees above the top of the hole by about 3 inches, ramped up top soil to the top of the dirtball, and built a moat out of top soil around it. 18 trees were done this way.

I've provided these trees with a 1 year replacement guarantee, provided the owner waters them properly. I'm installing a chunk of dowel by each tree, adjacent to the root ball sticking about 4" into the ground. Their water peon can pull the stick, and feel inside the hole to see if the soil is damp or dry.

One fear I have is that the root ball will lodge in the top of the hole, and an air space develop underneath it. This, I guess is the ultimate in drainage. I've seen enough burrows under trees that it doesn't necessarily mean failure.

1. Am I in trouble? The guy is reasonable. I've told him I won't be free to replace any trees until next fall. I can afford to redo the entire job if I have to it's mostly my time involved. (I grow the trees, and right now I've got more trees than customers I'm also in the area every two weeks, and so can check that he's watering them properly.

2. What's the best technique to deal with very heavy clay in planting sub-calliper trees?

It sounds like you have a pretty poorly draining and anaerobic backfill soil surrounded by poorly draining native soil. What I would do is put in drainage tubes. I would auger 6 inch diameter holes and insert 4 inch perforated PVC pipes. Then backfill around the pipes with gravel. Some people put a filter fabric sock around the tubes but I see those plug up with silt and clay particles pretty often, which severely limits the effectiveness of the drain. When digging to install the drainage tubes, it's ideal if you can punch through the heavy soil to a more coarse layer beneath. If that isn't feasible, then you'll just have to keep pumping out the sump if it fills up. The bigger the sump, the less pumping you'll have to do. If these are on a slope or there is low ground somewhere nearby it would be great if you could install that tubes that reach to the bottom of the rootball, and then run sidways on a slight downward slope until they daylight out somewhere. If they need it, there is no rule against installing more than one drainage tube per tree.

As far as the trees planted below grade go, there isn't much you can do at this point short of digging them up and and re-planting above grade. Whatever you do, do not try to bring the grade up around the trunks of the trees. You'll just suffocate the roots and make the problem worse.

Even trees adapted to wet sites may not tolerate being plunged suddenly into a mire after being grown in better draining material. And there are different kinds of wet sites, with differing combinations of conditions. Many swamp species will be growing in a highly organic mud or muck in nature rather than a subsoil.

Unless you are saying you have enough trees that you can afford to give them away because is the soil likely to be better when you plant the replacements?

None of the trees have sunk significantly. I guess the packing I did was sufficient (or there is a big air space under the tree...)

A couple needed adjustments to the staking to keep them straight.

All are showing new growth.

Some of the aspen are being nibbled on by grasshoppers.

I may have pulled it off.

On the other hand, 'rainy season' is a stretch. Currently in this part of Alberta we are running the driest year in 50 years -- about 40% of normal moisture levels over the course of the last year. We've had 5.5 inches of precip total since the first of April. And spring run off filled the 30" culvert under the lease road to a terrifying 2" depth.

The guy I did it for takes the watering seriously. This is why I went to check up on it. Each was damp, but not soggy, so he's doing his job.

We'll see.

The lesson remains: Always take a shovel when bidding on a planting contract.