Common Name Eremurus, Foxtail Lily 
Genus  Eremurus 
Species E. x isabellinus and other hybrids 
Family Asphodeloideae
Life Cycle  Perennial 
Root Count  50 roots per crate 
Care Eremurus bare roots will ship to you from the Netherlands in mid-October. They will have just entered dormancy prior to being dug and shipped. You likely won't see swelling buds or any active growth, and to the untrained eye they may look a little dead. Don't worry! They will establish some roots over fall and winter and wake up and start growing in the spring.

If you can't plant immediately on arrival store your roots in the cooler. The cold will keep them in the best condition until you are able to plant. Keep them from freezing and be sure to plant directly into your prepared bed before the soil freezes.

This is a carefully orchestrated process to get plants quickly from the growers field to you so please do your part and be ready to plant them on arrival. 
Netting / Staking Staking is not absolutely necessary - although these plants grow quite tall they are very sturdy and should stand up well. It would be beneficial to use a layer or two of netting in areas with high wind or extreme weather conditions.
Temperature Range Hardiness zones 5-8. Protect young shoots in the spring if they have started actively growing and there is a late frost warning. In colder zones it is a good idea to mulch with wood chips in the fall, providing some insulation for the roots. Be sure to leave the central crown exposed.
Spacing Plant roots 18-24" apart 
Soil Preference Organically rich, well draining soil is key when growing Eremurus - soggy soils will lead to root rot and crop failure. Prep the soil with compost and granular fertilizer and loosen the soil to a depth of about 6 inches. Sandy loam is ideal. 
Light  Eremurus should be planted in full sun. 
Pinching Do not pinch. 
When to Plant Plant in October as soon as possible after receiving the roots. Be careful when unboxing and planting as the fleshy roots can be fragile and may break easily. Dig a hole and make a small mound of soil in the center to hold the bud, pointed side upwards, at a depth of approximately 3 inches. Spread the roots out over the mound and back-fill with amended soil. Water in well after planting. 
Harvesting Harvest when the bottom florets have opened but the vast majority of the stem is still in bud for the longest vase life. The buds will continue to open in the vase.  
Post Harvest Care Cut stems should be placed into tepid water with a flower preservative and left overnight in a cooler to properly condition before using. Expect a vase life of 1-2 weeks. 
Diseases / Insects Eremurus are typically resistant to disease and insect pressures although young sprouts and soft new growth may be susceptible to slug and snail damage. Root rot due to soggy soil is the largest culprit of plant loss. This is a great option in areas with high deer pressure as eremurus are usually left untouched. 
Bailey's Notes

If you live in a warmer climate you might see some foliage start to grow soon after planting in the fall. This is OK - the plants will not flower until the following spring. After the flowers die back, the plant will gradually enter dormancy. Do not remove leaves that are green - let them continue photosynthesizing as this is what feeds the roots. Feel free to clean up the plants and remove the leaves once they have died back completely. Keep the soil damp during active growth and flowering but reduce watering when the plants enter dormancy. 

You may be tempted to plant an annual crop in the same area as your eremurus as they are dormant for a large part of the growing season. Resist the temptation! Eremurus are sensitive to root disturbance and even gentle cultivation around the roots can be disruptive. If you would like to interplant with other crops, choose perennial plants that do not require annual maintenance to the roots. Peonies, iris and roses make great neighbors to eremurus. Eremurus plants will continue to grow in size with more crowns and flower spikes developing each growth cycle. 

Resources

Cut Eremurus Care 

Eremurus Cultivation