MULTI-BUY 3 x 1 litre sized pots for $20. 1 litre sized pot. Helianthemum nummularium is known as the common rock rose and native to most of Europe. They thrive in a sunny position, coping with dry soil. Look great spilling over a pot or in a rock garden. It has delicate yellow flowers and sprawling medium-dark green foliage comprising of tough little leaves. Selecting this option gives you 3 x 1 litre sized Helianthemum nummularium for $20.