'Sky Pencil' Hollies Dead/Dying

[under_the_hill]

I installed 30 'Sky Pencil' Ilex crenata for a customer on May 30th on the edge of the customer's property. I placed them in a trench approximately 50 feet long, dug to leave the root flare approximately 2 inches above the ground, backfilled with native soil + 50/50 screened soil/compost (about 2:1 ratio) and added 3 inches of hardwood mulch on top, but off the trunk. The site slopes downwards before hitting a flat where a drain for rain runoff from the neighbor's property is taken. It rained during the 2nd day of installation but there has been little significant rain since then and temps from low 80s to mid 90s. Site if full sun, except towards the backyard which is part sun. Hollies came from a local nursery, container grown, 10 gallon.

I revisited about 1 week later to locate the customer's drip irrigation main line. The trees all looked healthy. Today I received the attached images, taken today. 10 of the trees appear to be dead or dying - I'll visit the site tomorrow. There must be green trees to the left as well as those shown to the right (towards the backyard) based on counts.

Customer indicated watering each evening until the drip irrigation line was installed (the day I located the line) and then the customer runs the drip irrigation line 10 minutes each evening.

I'm not adding my thoughts to avoid prejudicing your conclusions. What do you think is going on? What would you look for on a site visit?

 

[under_the_hill]

I visited the site and it's almost certainly the poor drainage of the lower section combined with the twice a day drip irrigation (or possibly frequent rain, not much in my area, but may have been in this area). There was standing water next to the lowest point, for example.

Hollies were planted high, so that leaves creating a berm or installing an additional drainage system to make replacements work.

 

[Jason Douglas]

Yep, most hollies are intolerant of low soil O2 from lots of water. If the soil in your area is heavy and fine textured, hollies may not work for you there.