This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
This is a charming plant for pot-culture, and the numbers of it sold in pots are immense, but to see it in its most effective dress it must be seen as a bedding-plant. In brilliancy it eclipses the well-known Viola Perpetual Yellow, and that is saying much for it. Treated exactly like Violas as to propagation, and being planted in good holding rich soil, its productiveness of bloom is wonderful. All through the past unfavourable season it has been a mass of bloom. No matter if it be battered for days or weeks with rain, two or three hours fair weather restores its brilliancy. It was from seeing it so brilliant at one or two places in England last year, when the weather was hot and dry, that induced us to plant a good many beds of it this year - and nothing in its way could be more satisfactory. Of course, it is all but hardy, if not quite so. At all events, treated just like Violas or Calceolarias, it will do well; and we are sure that all who want brilliant beds of yellow will not be disappointed if they grow this Musk in good soil. In hungry dry soils it would be well to put a good proportion of rotten manure in the beds.
All the Mimulus like moist rich soil.