Alistair Macdonald wrote:
From a bed of around 100 hybrid rose bushes, this year again I have
lost about ten plants, this after a rather poor flowering season. The
bed is well covered with forest bark but which I feel is not allowing
any feed to penetrate satisfactorily. I want first of all to provide
a better feed than Growmore, and also to plant new rose bushes to
replace those lost. What fertiliser(s) should I use for the existing
bushes and what, if different, for the new ones? I have been
recommended bone meal and sulphate of potash with a handful of Epsom
salts to each, both old and new bushes. I would also appreciate any
advice on applications.

I use horse manure liberally. It is easier to come by in some places than
others so if you don't have horses nearby I would suggest compost or other
herbivore manures. Chemical fertiliser alone is insufficient. I work on
mainly compost and manures topped off with inorganics (lime, gypsum, potash
etc) where required. I am not a rose enthisiast and don't have many but
they often grow 2.5 m (8ft ) in a season and all flower bountifully.

Epsom salts (magnesium sulphate) provides magnesium which is important to
plants but a handfull per plant seems a lot. A agronomist who teaches in
the district tells me that magnesium-calcium balance is quite important for
healthy soil and calcium must predominate so that by adding excess of
magnesium you may actually be worse off. Do you have reason to think your
soil is deficient in magnesium?

David