On 04/08/2014 19:21, FrankB wrote:
Planning to grow a patio rose in a pot but a few questions arise.

What is the minimum suitable size pot (height, diameter) recommended or
volume of pot?
Also what typeof compost is most suitable? John Innes 3, or multi-purpose?
Will the soil need to be changed each year or can the same soil stay in the
pot for a few years?





The size of pot depends on the type and size of rose. A large shrub rose
or smaller climbing rose should be planted in a large, deep pot, say 18"
(45cm) diameter. (I wouldn't be happy putting a large climbing rose in
a pot). A small patio rose might get away with a 12" (30cm) diameter
pot for a season or so, but a slightly bigger pot for longer term.

JI3 would be suitable for a rose, although I always mix in some
multi-purpose to open it up. I wouldn't want to use just multi-purpose
(except perhaps for a patio rose) as there isn't enough weight to keep
the pot stable in wind. I'm sure you could also use a purpose-made Tree
and Shrub compost. The compost will contain enough fertiliser for
roughly 6 months. After that, the rose will be dependent on you for
food and, of course, water. If the rose becomes stressed, it will be
much more prone to black spot.

You can certainly leave the rose in the same compost for 2-3yrs, but it
is a good idea to 'top dress' the pot each spring. This simply means
scraping away the top layer of old compost, including any weeds, moss or
liverworts. Take care as you meet the uppermost roots. Finally, dress
the top of the pot with fresh compost to the same level as it was
before. If you use a dry feed, you can mix this with the compost as you
top dress. Otherwise, water with a rose fertiliser to settle the soil.
--
Spider.
On high ground in SE London
gardening on heavy clay