If you’re planning an iris garden, here are a few tips you can use on how to plant an iris garden successfully.
What is the best way to plant?
When planting an iris rhizome, make sure the top of the rhizome (iris root) is level with the soil’s surface in moderate winter regions and about an inch below the surface in cold (daytime freezing) winter locations.
Plant higher rather than deeper by spreading out the roots face downward on a mound of dirt and packing the earth tightly around the roots to minimize air pockets.
The distance between various kinds (names) should be between 2 and 3 feet. Some types should be spaced around one foot apart. By the second or third year, they will be fully filled in.

Iris size classification
- MDB – Miniature Dwarf Bearded: below 8″ tall
- SDB – Standard Dwarf Bearded: 8″ to 16″ tall
- BB – Border Bearded: 16″ to 27 1/2″ tall
- MTB – Miniature Tall Bearded: 16″ to 27 1/2″ tall
- IB – Intermediate Bearded: 16″ to 27 1/2″ tall
- TB – Tall Bearded: over 27 1/2″ tall
How much light does Iris need?
Iris plants require at least 7 hours of direct sunshine every day to blossom well. Irises would thrive in full-light locations in your yard over the winter and spring. During the scorching summer days in California, Iris can withstand moderate shade ( or similar climate).
Plant in full sunlight. The shade will only reduce the number of blooms a plant produces.
Plant so the roots are in the ground, but the swollen central part of the root is lying on the ground – uncovered. If you cover this over too deeply, the plant will not bloom.
What is the best soil type for Iris?
Iris plants may thrive in any soil that drains well. Water should never pool at the base of the plants since it can rot them. Potting soil may simply be used to build up heavy clay and sandy soils. Simply raise flower beds a few inches in places with poor drainage.
What kind of fertilizer does Iris need?
Irises are robust feeders, and they should be fertilized twice a year with a balanced fertilizer like 6-10-10 or 15-15-15. Irises should never be fertilized with heavy nitrogen fertilizer (30-10-10). Fertilizer can be mixed into the soil at the time of planting.
Valentine’s Day and Labor Day are good reminders to fertilize. However, these dates may need to be adjusted for your hardiness zone.
How much water do Irises need?
Irises roots should be maintained wet but not soggy or swampy immediately after planting. Keep the plants moist until the winter rains arrive in the West, and then let the rain take over when the rain stops.
During the summer, water the plants once a week or so. This is critical for iris reblooming since they will not bloom without summer water. As long as there is adequate drainage, automatic sprinkler systems will suffice. Overwatering is a common mistake that can result in illness or soft, smelly rot.
How can I divide and transplant Irises?
Iris rhizomes can be split and planted from mid-summer to six weeks before frost for optimum results. You should divide your irises every four to five years. Dig out the clump, remove the dirt, then twist or cut the rhizome at each junction with a knife.
Each potato-like mass has a joint between it. Then, using scissors, cut the leaves back to 5-6 inches and the roots to 3 inches. Sort irises and replant rhizomes that appear to be healthy. Extras can visit new places or spend time with friends and relatives. Irises of the same kind (color) should be planted about 12 inches apart.
Iris Garden Design: How To Plant An Iris Garden

If you’re only growing a few plants, arrange them in your own iris garden in a triangle shape. The point of the triangle should point towards the spot you see this garden from.
This arrangement gives a sense of depth to the small planting.
In more extensive plantings, try to make a large block of these plants for maximum effect. Note that if you’re only growing a few iris of different colors, then another plan is to mix them into the general garden and surround them with perennials. This allows you to hide the foliage after the massive blooms are finished.
General Isis Garden Maintenance
There is very little maintenance required. When old leaves slide away without resistance, it’s time to get rid of them. Your iris flower can be pollinated by bees, resulting in a seed pod (egg-shaped). To avoid your garden from being overrun by some new UNWANTED iris flower color, remove old bloom stems (containing seed pods). Weeds should surround plants to allow for proper air circulation.
Use variegated foliage iris up front where the variegation can be appreciated.
Color choice is whatever suits your fancy but do try to arrange the flowers so that contrasting colors are beside each other (yellow next to blue) for maximum “bang” in the garden design.
Plant fragrant species next to the edge of the garden to make it easier to bend and smell them.
And those would be the main tips in planting and growing an iris garden.
How to care for Irises?
Iris is recognized by their rhizome, which stores nutrients and moisture and resembles somewhat chunky fingers. They are also recognized by the beards, which are found on the lower petals or falls and resembles a furry caterpillar.
These are often brightly colored and very distinctive. For instance, Bearded Iris needs to be planted in an open spot that receives sun at least half a day. They like a rich composted neutral to alkaline soil that must be free draining.
Plant so that the top of the rhizome is exposed to bake in the sun. Tuck the roots firmly into the soil—water in. A common mistake is to plant the rhizome too deeply.

Iris appreciates a light application of fertilizer in early spring and again a month after bloom. Never use animal manure as it is too high in nitrogen. I use a mix of 3 parts superphosphate, 2 parts blood and bone, and 1 part potash. If this is too hard, then a rose fertilizer would do.
Remove old leaves regularly and snap off the old stem down at the rhizome when flowering is finished.
Apply lime sulfur spray during the winter, and a rose spray against leafspot and aphids during the summer.
After about three to four years, the clumps will need dividing up. Dig up the whole clump, discard the old growth and replant the new rhizomes, which will be on the outside of the clump. January through to March is a good time to do this. The plant will produce new roots and needs to do this before winter.
Watch this awesome iris garden tour!
Descriptive terms for Iris plant
- Beards – Each of the falls has a line of fuzzy hairs at the top.
- The upper three petals are the standards.
- Lower three petals of the falls
- Bicolor – standards are single color, and falls have different color varieties
- Bi-tone – On the rises, a lighter tone of the same hue, and on the falls, a darker tone.
- Flounces are beard appendages that look like small flowers that emerge from the tip of the beard.
- Hafts are the tops of the falls (area surrounding beards)
- Horns are beard extensions that have been detached from the autumn petals.
- Plicata – A lighter ground color with a stippled or stitched margin color.
- Iris is a re-bloomer, meaning it blooms again in the late summer, fall, or winter.
- Shelf – Standards and falls are the same color tone
- Space Age – Iris with frills, horns, or spoons
- Spoons are protruding appendages from beards.
- Style Arms – Above the beards, a little stiff section
Who can name an Iris?
A human (hybridizer) permits two iris flowers to cross-pollinate and create a seed pod. A pod yields around 100 seeds gathered and sown (with exact records denoting pod parent and pollen parent, etc.).
The iris plants bloom after two or three years, and the hybridizer selects which ones are worth viewing the following year. Plants that are deemed unacceptable are destroyed. After two or three years of evaluating growth patterns and bloom colors, acceptable plants are named and registered with the American Iris Society.
A name cannot be duplicated, and picking a name necessitates a couple of pages of guidelines. It takes 5 to 7 years to complete the process.