GoodSeed Farm > Iris Planting Tips

Iris Planting Tips



Colorful Iris – Orchids for the Lazy

If you have a patch of Bearded Iris in your yard, you know how spectacular they can be with almost no care at all. Anyone can grow Bearded iris, a diverse group of plants with large showy blooms of virtually any color except bright red. This kind of iris gets its name from a patch of soft bristles on the lower petals of the flowers. There are actually three basic types of Iris: Bearded Iris (Iris germanica), Siberian Iris and Japanese Iris. Bearded Iris are the most common, so we’ll leave the other two types for a future column.

Late summer/early fall is the best time to plant new iris plants, so this is also the best time to rejuvenate your existing Iris patch. If you’re planting new Iris plants, seek out “reblooming” Iris varieties like “Immortality”, “Sugar Blues” or “Pure as Gold”, so you can have fall color as well as spring color in your Iris garden.

Bearded Iris do best in full sun, and they thrive in well-drained dry locations on high ground. Iris tubers, called rhizomes, resemble a bunch of small potatoes attached to each other end-to- end. Established Iris really benefit from occasional housekeeping. Over time they get too crowded, infested with tiny Iris worms, and start to rot. Digging them up and dividing them gives them a fresh start, and it multiplies the number of blooms.

Like potatoes, Iris tubers can be easily bruised. Use a digging fork instead of a shovel, to avoid damaging them or cutting the many roots underneath each tuber. If you let them dry for a bit, it’s easier to brush the dirt off without hurting them. Now, break them apart and toss any tubers that are rotted, or pockmarked with worm holes. Each healthy tuber should have a fan of green leaves. Trim the leaves, leaving 3 to 5 inches sticking out from the tuber.

To prepare your planting bed, till the soil six inches deep, working in some bone meal or Bulb Tone. Avoid high-nitrogen fertilizers like 10-10-10 or Miracle-Gro; too much nitrogen will give you healthy leaves but few blooms.

Iris tubers resemble crawdads or shrimp; the roots sticking out from the bottom look like shrimp legs. Tuck the roots into the loosened soil, LEAVING THE TOPS OF THE TUBERS EXPOSED. Iris plants will not bloom if planted too deep. Water the plants, for the first and only time. Too much moisture will rot your Iris.

Weeds are the biggest challenge in Iris beds because, if you mulch them heavily enough to smother weeds, the Iris will be smothered as well. You can’t use Preen because it will damage the tender tubers and melt the Iris leaves. The best solution is to lightly mulch with pine bark nuggets or pine straw, which won’t get soggy or pack down, and will allow the plants to breathe.

Our tongue-in-cheek planting instructions for Iris are as follows: Till the iris patch, (preferably hard, dry, exhausted clay soil in the broiling sun) until it’s fluffy and powdery. Throw your Iris tubers in the air, so they land on the freshly tilled soil. Then walk away.

We’re sharing this exaggerated planting method with you to make a point: the care and coddling you would give any other flower or vegetable plant will most likely kill your Iris with kindness, or at the very least prevent them from blooming. We often see struggling Iris patches in landscapes, a sign of soggy soil, over-mulching and/or planting too deep. If these poor, smothered plants were dug up and tossed aside, they would probably recover nicely and bloom their hearts out, sitting on top of the ground.