Product Field NotesCompanion Plants
Caesar's Brother Siberian Iris: Deep Purple Since 1932
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Caesar's Brother Siberian iris was introduced in 1932, and gardeners are still planting it for good reason. In early summer it blooms heavily, with many solid deep purple flowers open at once, each marked by a small yellow and white blaze lined with dark veins. It won the American Iris Society's Morgan Award in 1953.
Its color is a natural match for a lavender garden, but its needs are not quite the same. Siberian irises like steadier moisture, so Caesar's Brother belongs in a moister border nearby, where its purple opens just before the lavender's.
Caesar's Brother at a glance
| Trait | What to expect |
|---|---|
| Botanical name | Iris sibirica 'Caesar's Brother' |
| Flowers | Deep purple with a small yellow and white blaze |
| Foliage | Tall, grassy, mid-green, attractive until frost |
| Size | 36 to 42 inches tall, 18 to 24 inches wide |
| Bloom | Early to mid-June |
| Hardiness | USDA zones 3 to 9 |
| Light | Full sun to part shade |
| Deer | Resistant |
Purple before the purple
A lavender garden that wants a long purple season can use Caesar's Brother as the opening act. It flowers in early to mid-June, often just before English lavenders reach full color. Plant a band of it along the moister edge of the property, such as a rain garden, the lawn side of a border or a pond bank, and the purple starts there before moving to the lavender beds.
It is tall, up to three and a half feet, with an upright, vase-shaped clump of grassy leaves that stays good-looking until frost. That height and fine texture make a strong vertical contrast to lavender's low mounds when the two are planted within view of each other. Lay out moist and dry areas together in the Companion Plant Planner.
Planting and care
- Soil: average to rich, kept moist through the season, especially in spring and early summer.
- Summer: water deeply in hot, dry spells so the foliage stays fresh after bloom.
- After bloom: cut spent flower stems back.
- Cleanup: cut foliage back in late fall or early spring. Established clumps need no winter mulch; it is hardy to zone 3.
- Dividing: split crowded clumps in late summer.
- Black walnut: not a problem for Siberian iris.
Pests and diseases are rare. Iris leaf spot occasionally appears, rot threatens only in waterlogged soil and iris borer is much less of an issue than with bearded irises.
For the vase
Caesar's Brother rates well as a cut flower. Cut stems as the first bud opens. Deep purple iris with a few early lavender spikes makes an all-purple bouquet with two very different shapes.
Ordering format
Caesar's Brother is offered as a bare root plant. See the product page for current availability.
Frequently asked questions
Why is it sometimes spelled differently?
Its original registered spelling was 'Caezar's Brother'. Both names refer to the same iris.
Does it rebloom?
Rebloom is low. It puts everything into one heavy show in June.
Can it grow in a rain garden?
Yes. It is listed for rain gardens and pond edges, where its love of moisture is an advantage.
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