The foxtail lily (Eremurus robustus) is often described as a bulb, but it is actually a perennial tuberous root that sends up bottle-brush spires of densely packed flowers from late spring into early summer. Depending on the variety, the plant grows 3 to 8 feet tall, with blooms in warm shades of yellow, orange, pink, and coral. Its strappy leaves form a rosette at the base, and the whole plant is deer-resistant. Gardeners who already grow alstroemeria can transfer the same Peruvian lily care habits of staking and steady moisture to this taller relative.
Foxtail lilies earn the common names desert candle and king’s spears because a mature clump reads like a column of flame in the border. The vertical habit makes them a reliable accent for the back of a mixed bed, along a fence line, or against a wall where the spikes can rise without shading shorter neighbors. Because the plants go dormant in summer, they pair well with later-blooming perennials that fill the gap left by the dying foliage.
Foxtail lilies bloom for two to three weeks per spike, and because the flowers open from the bottom of the raceme upward, the display lasts longer than a single flush of color. Cutting spikes for vases works well, but leave at least two spikes per plant so the tuber rebuilds its energy reserves for the following year.
Understanding Foxtail Lily Growth Habits
The tuberous root system stores the energy that drives the flower spike. Unlike true bulbs, which layer scales around a bud, foxtail lily roots are thick, fleshy, and star-shaped, spreading outward from a central crown. The crown sits near the soil surface, which is why drainage and winter protection matter more than planting depth. Each spring the rosette of strappy leaves appears first, then the spike elongates rapidly once warm weather arrives.
Hardiness Zones and Climate
Foxtail lilies thrive in USDA zones 5 to 8, where a period of cool winter weather triggers the bloom cycle. In zone 8, choose a site with afternoon shade so the roots do not bake during summer dormancy. In the colder part of zone 5, a thick winter mulch or a sheltered spot against a south-facing wall helps the crown survive hard freezes.
Growth Rates and Mature Size
Eremurus robustus is the tallest species, reaching 6 to 8 feet in good soil, while smaller species such as Eremurus stenophyllus top out near 3 to 4 feet. The plants grow quickly once established; a first-year tuber often produces a full spike, and clumps widen as the roots multiply. Expect a mature spread of about 2 feet per plant.
Choosing Varieties
Garden centers sell both species and named hybrids, with flower colors ranging from pale yellow and white through orange and coral-pink. Bloom time stretches from late spring into early summer, with the shorter species flowering first. For a staggered display, combine an early dwarf with a tall late bloomer in the same bed.
In the wild, Eremurus species grow on rocky steppes and mountain slopes from central Asia to the Himalayas, where snowmelt waters the roots in spring and the dry summer sends the plants into dormancy. Recreating that rhythm in a garden means generous spring moisture, good drainage, and a dry rest after the foliage dies back.
Site Selection and Soil Preparation
Full sun produces stronger plants and straighter spikes. Give foxtail lilies at least 6 hours of direct light, and more in cool climates. The soil should be sandy to loamy with sharp drainage; the plants tolerate acid, alkaline, and neutral pH, so most garden soils work as long as they do not stay wet. Raised beds and sloped sites drain faster than flat, heavy ground.
Testing Drainage Before Planting
Dig a hole 12 inches deep and wide, fill it with water, and check it the next morning. If water remains after 24 hours, the spot is too wet for foxtail lilies unless you raise the planting surface. Working coarse sand and compost into the top 12 inches improves both drainage and nutrient holding, but do not bury the crown below the surrounding grade.
Amending Heavy Soil
Clay soil is the most common failure point. Build a low mound 8 to 12 inches high, blend in grit or coarse sand, and plant into the mound so the crown sits above the water table of the surrounding bed. Keep the planting away from downspouts, low spots, and irrigation heads that puddle. If dogs share the yard, check which lilies are poisonous to dogs before adding any lily relative to the border.
Container growing is a workable alternative where the ground stays wet. Use a deep pot at least 18 inches across, fill it with gritty potting mix, and move it to a protected spot in winter. The same drainage rules apply: the crown must never sit in standing water, and the pot needs a hole large enough to shed heavy rain.
Planting Foxtail Lily Tubers Step by Step
Plant foxtail lilies in the fall, about six weeks before the ground freezes, so the roots establish before dormancy. Buy firm, plump tubers and set them out as soon as they arrive, because the fleshy roots dry out quickly.
- Choose a sunny, well-drained spot prepared the season before if possible.
- Dig a hole wide enough to spread the roots horizontally without bending them.
- Set the crown 4 to 6 inches below the surface, with the bud facing up.
- Space plants 18 to 24 inches apart for tall species, 12 to 18 inches for dwarfs.
- Backfill with native soil and water deeply once to settle the soil.
- Mark each spot with a stake, because a dormant tuber is invisible until spring.
Depth and Spacing
Depth and spacing vary with species. Plant Eremurus robustus with the crown 5 to 6 inches deep and 24 inches apart; smaller species sit 3 to 4 inches deep and 12 to 18 inches apart. Closer spacing gives a denser flower display but shortens the life of each crown as the roots compete.
Tuber Orientation
The crown carries the growth bud, and the thick roots radiate from it like spokes. Set the crown facing up and let the roots lie flat in the hole. A tuber planted upside down still grows, but it wastes a season reorienting itself.
| Factor | Foxtail Lily Requirement |
|---|---|
| Sun | Full sun, 6 or more hours |
| Soil | Sandy to loamy, sharp drainage |
| Soil pH | Acid, alkaline, or neutral |
| Planting time | Fall, 6 weeks before frost |
| Crown depth | 3 to 6 inches by species |
| Spacing | 12 to 24 inches |
| Hardiness | USDA zones 5 to 8 |
Planting in groups of three or five produces a stronger display than single tubers scattered across a bed. Stagger the planting depth slightly so the spikes mature at different times, and place the tallest species at the back where their height frames shorter neighbors.
Watering, Feeding, and Seasonal Maintenance
Water well at planting, then keep the soil somewhat moist while the spike grows, never soggy. Once established, foxtail lilies tolerate dry spells because the tuber stores moisture. During bloom, a steady supply of water extends the flowering period, while drought shortens it and can abort the topmost buds.
Fertilizer Schedule
Feed the growing flower spike with a balanced, low-nitrogen fertilizer in early spring as the rosette emerges. Too much nitrogen pushes leafy growth at the expense of flowers. A second light feeding after bloom rebuilds the tuber for the next season. Slow-release formulas applied at the drip line work well.
Mulching and Staking
A 2- to 3-inch layer of mulch in spring keeps the crown cool and holds moisture, but pull it back from the crown itself to avoid rot. Tall spikes lean in open, windy sites; drive a stake in early and tie the stem loosely so the support is hidden by the foliage. Remove the stake after bloom.
- Early spring: pull mulch back, apply balanced fertilizer, watch for new shoots
- Late spring: stake tall spikes, water during dry spells
- Summer: let foliage yellow and die back naturally
- Fall: cut spent foliage, plant new tubers, mulch for winter
Deadheading is optional on foxtail lilies. Removing spent spikes keeps the bed tidy, but the seed heads add structure in late summer and self-sown seedlings occasionally appear near the parent plant. If you deadhead, cut the stalk at the base rather than pulling, so the crown is not disturbed.
Pests, Diseases, and Winter Protection
Foxtail lilies have few serious pests. Deer leave them alone, and rabbits usually pass by the crown. Slugs and snails chew new shoots in wet springs, and aphids occasionally cluster on flower spikes; wash them off with a strong stream of water or treat with insecticidal soap.
Common Diseases
Root rot from chronically wet soil kills more foxtail lilies than any pest. The first sign is foliage that yellows and collapses in spring, followed by a soft, smelly crown. Improve drainage before replanting. Leaf spot and rust appear in humid climates; remove affected foliage and improve air circulation around the clump.
Overwintering in Cold Zones
In zone 5, cover the crown with 4 to 6 inches of mulch after the ground freezes, then pull it back in early spring. Gardeners in colder zones can dig the tubers after the foliage dies, store them in barely moist peat in a cool place, and replant in spring. Container-grown plants overwinter best in an unheated garage.
Planted against a south-facing wall with well-drained soil, foxtail lilies return year after year and multiply into a colony that anchors the back of a border. The combination of deer resistance, drought tolerance, and a dramatic vertical bloom makes them one of the easiest statement plants for a sunny perennial bed.