Learn how to grow Dutch iris and other small iris types.
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There are two common types of bulb iris. The species is iris reticulata. It’s a hardy bulb with fragrant purple flowers and yellow streaks. It grows 4 to 6 inches tall making for a beautiful rock garden and low flower border plant. The Dutch hybrid bulb irises have larger flowers and are taller plants, stretching up to 1 to 2 feet tall. They are often used as cut flowers and come in blue, yellow or white colored varieties.
The species bulb iris bloom around the time of snow drops and early crocus, while the Dutch hybrids bloom about a month later. While the species is reliably hardy to USDA zone 5, Dutch hybrids are not long lived and may need winter protection in our colder climate. Many just grow these as annuals, replanting each fall. A good selling point, though, is deer don’t seem to like either of these iris.
Unlike bearded and Siberian iris, these iris grow from fall planted bulbs. Plant in a full sun on well-drained soil. Loosen the soil well, amend it with compost and plant the onion-shaped bulbs 5 inches deep. Plant with the hairy root side down and pointed tip up. Water well. If mice and voles are a problem, add a few handfuls of crushed seashells or oyster shells to the hole to discourage them. They don’t like the sharp, pointy crushed shells. For problem critters, consider buying or building a wire cage to sink in the ground and plant the bulbs in.
From the Vermont Garden Journal.