I have a 15 year old myrtle bush that haven't flowered in about three years now,but keep growing. In the summer i fed with seaweed fertilizer. Can anyone help as when i should prune spring or autumn.
Vendée, Western France
edited October 2018
The RHS advises a late spring prune as these plants flower on growth made the previous year. In order to rejuvenate it you need to remove any obviously dead or damages stems back to their main branch. Then look at the shape and remove up to one third of the oldest looking stems. Then weed at the base and give it a general purpose feed and a mulch of well-rotted garden compost or manure.
In succeeding years you repeat the process, removing the oldest stems again and thus rejuvenating your shrub every 3 years and, with any luck, re-invigorating its urge to flower.
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw