IMHO ... established trees... conifers.. and shrubs.. never need any fert... or food... in your case.. they are shrubs.. not children ...

and i wouldnt go digging in stuff under such .... it will cause a lot of shrubs to start suckering wildly ...

mulch is enough ...

we ought to ID the hollies... to be sure there arent differences.. depending on type ... a pic of such here.. or in the name that plant forum ... will probably get you an ID ...

next ..... we need a pic.. to give you pertinent info on pruning ....

we need to know where you are.. z5 includes just about half the US ... it might matter ...

finally??? ... lol ... as to the cold ... they have been there for decades ... and i doubt your recent cold snap is worse that what it has seen before ... you might end up with some damage.. which can be pruned out... but that is common with growing any shrubs ...

on some level ... you are thinking of you Hs as your new .... 20 year old babies ... most shrubs are 'run them over with the truck, and they could care less' ... type plants ... they simply dont need all that much ...

one problem with 20 year old shrubs.. is that when they were planted.. in your case... 20 years ago.. they might have been in full sun ... and now.. they are in full shade ... and that MIGHT be why ... they are not thriving like they used to ... so i am back to saying.. lets have a look/see at them.. so we can really give some good advice ...

i really dont know why i use the term FINALLY ... it never is... lol ...

pix please...

ken

One thought superseded with another and another and on rolls the mind.lol

Are hollies like boxwood in that they don't replace dead leaves.

'Are hollies like boxwood in that they don't replace dead leaves.'
I'm not quite sure what that means because both Box and Holly can be cut back very hard and will re grow. I've had a Holly uprooted and lying around the garden for a few weeks before replanting and pruning. Off it went - no problem. That applies to Ilex aquifolium and its cultivars. I can't speak for other species/hybrids. I agree we need to id the Hollies. The Shrub forum might be able to add more info. if we run out of ideas here.

Here is a link that might be useful: Shrubs forum

Like Ken said, they're bulletproof.

I had a tenant stick a 3gallon Burford holly in a 3 gallon sized hole of rock hard red clay, I won't say it's thrived, but it has continued to grow.

If they are burning up during recent winters it sounds like they aren't going to work out there anyway, regardless of other circumstances. Otherwise the thing to do about the cold damage would be to mulch the root zones and let the tops come back on their own, as they may. After they fill back in any bits here and there that don't look right can be cut out. But cutting remaining live tops down to stumps in reaction to recent cold damage will just add insult to injury, force them to draw on stored energy in the roots to replace the lost top growth.

Intact specimens that had not been defoliated by cold beforehand would be starting with full compliments of energy to replace the cut tops. But even when cutting down a healthy box or holly response is at first quite limited because of the now greatly reduced energy available for making a new top. When not cut on trees and shrubs use energy stored in branches, trunks and roots to produce new stem growth.

Digging under trees and shrubs just damages the feeder roots, something that is not of any benefit to them.

This post was edited by bboy on Thu, Jan 8, 15 at 13:08

bboy is right - I should have been more specific. You can cut happy box or holly back hard. If they are unhappy they need to be got healthy before any surgery.

Yes they most certainly can be cut back. I do this regularly.
A branch whose leaves have brown however won't produce fresh foliage after winter and would need trimmed.

It sounds like these plants are misshapen and half dead. I'd remove them and plant something new that would like the shady, sandy spot.

Holly do replace dead leaves, but more slowly then deciduous trees. If they ever lose *ALL* their leaves they are probably dead. If they lose a few they will grow them back.

You could try using hollytone.

There are many species of holly, but I suspect some of the more common ones would be borderline hardy in zone 5. Shelter from the wind in the winter might help. (eg a tarp).