rosemary bush

The Rosemary Incident

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Question by: Sarah L

Hi Sarah, I am seeking advice on how to get my rosemary bushes back to life after a gardener came in and chopped it back way too much in the middle of a heat wave. The rosemary bushes would have to be close to 20 years old and before the gardener came they had a good few more years left in them.

In most parts the gardener cut them back to the old stock part and from my understanding new growth doesn’t spurt from that. They were very green and lush and now quite sticky and can see through the bush. I would be devastated if I now have to pull them out. They are at the main entrance to my home and stand at shoulder height.

Sarah's answer

Hi Sarah. Gosh that must have been quite upsetting for you.

While generally not recommended, a mature rosemary plant can tolerate drastic pruning into the woody stem, however hard pruning is normally suggested for the cool of late spring when the plant is not actively growing, not the height of summer. It should really be done slowly and gently by taking a third away every 6–8 weeks.

The severe pruning itself may not kill the plant, however, if the canopy is severely reduced the plant may struggle to produce enough energy through photosynthesis to grow as well as regenerate new leaves. It also makes it vulnerable to attack from pest and disease.

To help minimise the harm, make sure it is well fertilised and well-watered so the plant has what it needs readily available. Generally rosemary doesn't need much food and water as they can manage on their own, however continuing to ensure the soil stays moist deep down (a deep watering once a week is better than shallow waterings daily) and a light feed with a general purpose fertiliser will make sure the plant doesn't have to work too hard to find what it needs. Having said that we are looking for a slow and steady regrowth, not a fast and leafy as this can make it more vulnerable to pests and disease and if you get frosts, it is the wrong time of year to be encouraging masses of new growth, so don't overdo it.

Normally, in less than perfect soil the recommendation is to only fertilise a couple of times a year. Also a seaweed tonic can be of benefit to a plant under stress. It is a natural source of plant growth regulators, such as auxins, cytokinins, gibberellins and betaines, as well as alginates and minerals and when applied at low rates stimulates plant and root growth.

The only other thing it needs is time, and all going well it will recover. However, depending on just how severe the pruning, things may not go well. I’m sorry I can’t say for certain it will be OK, but I am hoping that it will manage to bounce back for you.

Cheers, Sarah