Question
We have well established hedges bordering the front garden made up of 3 or 4 plants (I think box or privet, not sure which (has small green leaves).  After a delivery of some stones/gravel for our drive, part of which borders the edge of the hedge the hedges started to die.  This started about 4 years ago and gradually spread across the whole hedge and now we are left with grey twiggy hedges with very little leaves.  Perhaps there was a chemical in with the stones?  the hedges needs to come and and replant I would imagine.  Please can you advise the best way to go about this, what time of year is best, what kind of hedge and how to prepare the ground?  We live in Hertfordshire and the ground is rocky and chalky.  Thank you so much.

Answer
Hello Katherine

Are (were) the leaves very small - about 1/2 an inch long?  If so this sounds like box and the die back you're seeing could well be caused by box blight.  This is an incurable fungal infection and usually 2 funguses are involved.  One causes the leaves to brown off and die and the other affects the stems.

I don't think that the gravel is to blame as it is well washed before being put onto the market.  No chemicals should be involved at all.

You are right - the very best thing you can do is dig up the hedge and replace it with a completely different plant.  My choice would be Escallonia (in fact, this is my choice for my front garden!).  There are lots of varieties of this plant - large leaves, small leaves, red, pink or white flowers all summer - and they can be clipped into a very tidy hedge, (left alone they do try to become trees!)  They are also not too fussy about soil type, as long as it's fertile, and are usually frost hardy down to about -5C.  We have had temperatures below that this winter and the hedge still looks good!

The time to plant will be once the ground has thawed out from the recent hard frosts and the earth has warmed up.  I don't think there is anything to be gained in waiting until later in the year.

The best, and to my mind the easiest, way to plant a new hedge, is:

Dig out the old plants and discard them.  Burn them if you can as this will ensure that the fungus isn't spread to other box plants in the vicinity.

Buy new plants - how many you need will depend on the length of the proposed hedge, I'd recommend one plant every 18" to 24". The plants can either be bought bare rooted or pot grown.  If you need to buy lots of plants, bare rooted are the cheapest option.

If you have bare rooted plants put them into a bucket of luke-warm water while you prepare the planting trench described below.

Dig a trench a foot or two longer than the proposed hedge, about 1.5 feet wide (or wide enough to accommodate pot grown plants without having to squash them in) and deep enough so that the top of the compost in the container is level with the surrounding soil - don't forget to take the plants out of the pots before you bury them!  (I know, I know - but you'd be surprised believe me!).  With bare rooted plants you will see a soil mark on the trunk - that will be your depth indicator.

Loosen the soil in the bottom of the trench and scatter bonemeal on the loose soil and lightly fork it in.  At the same time you can scatter some bonemeal on the dug out soil too.

Position the plants in the trench, stand back and have a good look to make sure they are well spaced.

Begin backfilling the trench - if the plants are barerooted hold each plant vertical until there is enough soil around the roots to hold it steady and give each plant a gentle shake every now and then to settle the earth around the roots.

When the trench is about half full, firm the soil in gently with your heel.

Continue with the filling until the soil is at its original ground level and firm in once more with your heel.

There may be some soil left over - just leave it where it is for now.

With a hose (if you have one) give the plants a really good puddling in - this means lots of water! - this settles the earth and gives the plants a much needed drink.

Rake any left over soil around the plants once the water has soaked in.

To finish, and to give the new hedge area a nice tidy appearance (and help to retain moisture), spread a mulch along the length of the trench - shredded bark would look really nice.

Be sure to water the new plants during dry spells for the first year, after that the plants should be able to take care of themselves, though you may want to add more mulch from time to time to keep up appearances!

I know this sounds like hard work, but it will be worth it - honestly!!

Gill