Eremurus are clump forming perennials with large fleshy roots around a central crown from which the leaf and flower will appear. We normally supply these plants as bare root crowns in October and November when they are fully dormant. Eremurus do not grow well or flower properly in pots unless you can find one large enough to accommodate the large rosette of roots which, in particular, E. robustus certainly has.
Eremurus are best planted in late autumn so that the crown is just below ground level and the fleshy roots are well embedded in the soil below. If kept dry in the potting shed and covered with newspaper or straw to keep any frost away there is no real rush to plant them in the ground until early March, but they do need to go in then. We find that these plants perform best if they have been frozen in the ground in a cold winter.
Foxtail lilies grow in the wild in dry grassland in central Asia. They prefer fertile sandy, well drained loam in full sun and with wind protection for their tall flower spikes. These may well need a stake to support them as they come into flower. A dry mulch over the plants in autumn (leaving the crown uncovered) is good practice.
The plants can be lifted and divided when a clump has formed after they die down which is fairly quickly after flowering finishes. We normally lift in September.
E. robustus has strap shaped bluish green leaves which, in maturity, can be 4ft long. Pale pink flowers appear in terminal conical racemes which can become 2-3ft long.
E. stenophyllus is also a tufted perennial but a rather smaller growing one. Its leaves are narrow, linear and grey-green. They are only 10in or so long and the flowering racemes are on stalks of up to 3ft in height. The flowers are dark yellow and offset nicely with the darker green of Astrantia or Echinops.
E. x isabellinus ‘Ruiter Hybrids’ come as a mixture with pink, yellow and gold coloured flowers. They are tough and easy to grow. The leaves and flowers are about half way between the size of those of E. robustus and E. stenophyllus which are the parents of this range of garden friendly hybrids. We have had some success getting these to flower in pots but the leaves tend to flop and the overall appearance in pots is unsightly as they flower. In the garden you do not have this problem.