This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Amongst the dwarfer shrubby kinds grown for rock gardens are carnosula, chathamica, Bidwelli, cupressoides, epacridea, Haasti, Hectori, Hulkeana, Lyalli, lycopodioides, pimelioides, salicornoides; all natives of New Zealand. Most of these are somewhat tender, and require protection in severe winters.
Perhaps the kinds which are grown most extensively are V. Andersoni, and its many beautiful varieties - all of hybrid origin. They are pretty shrubby plants, with elliptic glossy-green leaves and erect spikes of flowers in which there are now many beautiful shades of colour, such as rich purple, deep violet, pale blue, lavender, crimson, salmon pink, mauve, and pure white. There is a mere form with beautifully variegated leaves. A very old garden Veronica, V. angustifolia, at one time largely grown, is now rarely seen. It has narrow recurved leaves, and spikes of white flowers faintly tinted with lavender. V. Traversi (decussata) grows up to 6 ft. high, and is a charming evergreen with leaves arranged crosswise. The bluish-white flowers are borne in great profusion in summer.