How to make them bloom? I have a plant - prickly rose - for 3 years in a large pot outside and, alas, no blooms.
Prickly Rose (Rosa acicularis Lindl) has a rich heritage going back to old world times. Neat to have her. She is a once bloomer during Spring or Summer typically. She is tempermental about her growing conditions and prefers the forest lands. Trying to create the forest floor soils composition may help her to bloom but being in a pot could well hinder any bloom production. If the rose is subjected to some cold nights it is possible to easily lose the forming bloom buds and once they are gone it takes another year to have hopes of seeing her blooms. I have a rosebush called Dragon Wings or the Windthorn rose (Rosa Sericea Pteracantha) that I grow mainly for her amazing beautiful thorns. I have had her for three years and have not yet seen her bloom smiles.... Each year I hope to see them but not yet. They are both hardy roses and usually not all that fussy about soils type. However your Prickly Rose does seem to have a preference for the forest floor soils composition. So I would either plant her in the ground with soils amendments copying a typical forest floor, or transplant her into a larger pot with the same soils adjustments. Hopefully year four will be our year to finally see the precious blooms on our once a year blooming rosebushes.Here is a link to some limited information on your fine wild rose: http://www.helpmefind.com/rose/l.php?l=2.5251&tab=1