Bearded iris

Questions about bearded iris

Does bearded iris need sun or shade?

Bearded iris grows in full sun (6 or more hours of direct sun a day).

It wants dry, sharply drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.

What zones does bearded iris grow in?

USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).

Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.

When does bearded iris flower in my zone?

In zone 5 it flowers late May to mid June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.

Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.

How far apart should bearded iris be planted?

16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.

It grows 2½ ft (80 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many bearded iris plants do I need?

At 16 in apart, set out in staggered rows:

• 7 to fill 10 square feet (about 1 m²)
• 8 for a single row 10 ft (3 m) long
• 21 to fill a 4 × 8 ft bed on its own

In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.

In the bed above, the planner used two in two groups.

Is bearded iris poisonous to dogs and cats?

Yes: mild toxicity to people, dogs, cats and horses. The underground stems (rhizomes) and leaves can cause drooling and stomach upset if eaten.

Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.

Is there a pet-safe plant like bearded iris?

These come closest to doing what bearded iris does, and no toxicity is recorded for them:

• Meadow sage 'Caradonna': the same job in a bed and the same colour; 8 in shorter, flowers late May to mid July.
• Sea holly: the same job in a bed and the same size; flowers early July to mid August, blue, not purple.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

Do deer eat bearded iris?

Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.

What flowers after bearded iris?

Bearded iris is over by mid June. These start as it finishes and carry the same spot on, so it never goes flat:

• Black-eyed Susan: from mid July to mid September, 24 in tall, to stand in front of it and cover its fading stems.
• Butterfly weed: from late June to early August, 24 in tall, to stand in front of it and cover its fading stems.
• Yarrow: from mid June to late August, 24 in tall, to stand in front of it and cover its fading stems.

What does bearded iris look like in winter?

Bearded iris holds some of its leaves into winter, more in a mild year or a sheltered spot, and they look tired by March. Cut the old ones off as new growth starts.