For the Love of Iris

Articles, Tips and Notes from Schreiner's Iris Gardens

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The Whole “Scoop” on Fertilizing Iris

Customers often ask us, “How and when should I fertilizer my iris?”Fertilizer_NewBag2018web2 

The short answer (continue reading for the nitty-gritty): one month before bloom season, while the tulips are blooming, apply a low-nitrogen, well-balanced fertilizer, such as Schreiner’s 6-10-10 Controlled Release Iris Food. Keep the fertilizer several inches away from the rhizomes. Approximately on month after bloom season, fertilize again. That sums it up nicely, but perhaps you would like a bit more to chew on about the “what” and “when” of feeding your Iris. Read on for a more substantial serving of info on nurturing both your soil and your Iris.

There are four main nutrients that we must maintain in the soil: nitrogen, phosphorus, potassium, and calcium. The first three nutrients are found in most mixed fertilizers, and calcium can be purchased separately in the form of limestone. Nitrogen is necessary for new cell formation in all parts of a plant. Compared to other nutrients, nitrogen is typically the most lacking. A symptom of a shortage of nitrogen is yellow-green stunted growth. Potassium (potash) is necessary for strong roots and stems as well as deep flower color. A symptom of potash deficiency is weak stems and yellowing or browning leaf tips and edges. Phosphorus is necessary for development of roots and stems. This nutrient also stimulates fruit and seed production. A symptom of Phosphorus deficiency is red or purple discoloration of leaves.

Before applying any fertilizer to your garden, do a soil test to discover what your plants actually need. The best way to know how much, and at what proportion, to add nutrients to the soil is with a soil test. Simple soil tests can be purchased at garden supply centers. Once you determine what nutrients are lacking or are in abundance, you can amend the soil to correct most problems. Your soil test may also reveal a need to correct pH or add trace minerals, for example. Completing a soil test, and making modifications to your soil based on the results, is the preferred method to determine fertilizer amounts.

Fertilization of Iris is important to obtain best results, but must be done in moderation. The only thing Iris may resent more than underfeeding is overfeeding. Nitrogen, potash, and phosphorus are essential for Iris, but excessive nitrogen promotes lush growth that is more susceptible to rot diseases. If applied in concentrated form, do not allow the fertilizer to come in direct contact with foliage and roots, as the plant may be damaged or killed. Low-nitrogen fertilizers, such as 6-10-10, are ideal for the needs of Iris.

When to apply fertilizer to Iris:

1)   In the spring, about a month before bloom, apply a light application of fertilizer around the Iris clumps. This goes for dwarf iris, too, which bloom in March. Apply a low-Nitrogen fertilizer to your dwarf iris in mid to late February. Apply the same to your intermediate and tall bearded iris in intervals coinciding with the month before their bloom cycles.

2)  At planting, sprinkle a tablespoon of the fertilizer around the newly planted rhizome. Or, if preparing a large area for iris planting, incorporate ½ lb of a low-nitrogen fertilizer such as 6-10-10 per 50 ft2 (or 1 ½ oz per 10 ft2) to your garden bed.

3)  After your Iris bloom is another time you should fertilize them. Doing so keeps them healthy and in tiptop shape for better growth for the growing cycle later in the year. Wait a month or so after blooms have finished, or in the fall, with enough time before winter so the Iris have the proper nutrition they need going into their winter dormancy.

Here’s a little more info on the subject of fertilizing, including a short video with Ben Schreiner showing us how and when to feed your iris

Now that you’ve got the scoop on Iris nourishment, you can take the necessary action to feed your hungry Iris. Schreiner’s Gardens offers a specially formulated Iris food to help you provide balanced nutrition in the flower garden. Order now for summer and fall shipment.

Yours in gardening!

Information sourced from: and



Iridaceous Pink Artistry, Iris Winter Care, and Bulbs vs Rhizomes

Winter Iris Care  Does your Iris bed look like this right nowbearded-iris-in-snow…. under a foot of snow? Iris beds covered in a blanket of snow need no care at this time. Let nature’s insulator do its job.

bearded-iris-bedOr maybe they look something like this….a tangled mess of decayed leaves? Well, even though it’s not an ideal sight, don’t be ashamed. Let’s talk about how to remedy the situation.

If you have a garden that boasts bare ground right about now, you most likely are also starting to see signs of spring – along with the darling and beloved daffodil, tulip and hyacinth shoots, weeds and grass blades are also emerging. Now is a good time to dote upon the forgotten Iris bed, and trim back the dead, decayed foliage. If the leaves are droopy, brownish-gray — completely lifeless — then gently tear them off at the base, like a sheet of notebook paper from its spiral. If the leaves are still sturdy and green, trim those down to below any evidence of leaf spot.

Clear away the debris from the beds, pick out the emerging weeds, if any, from the soft soil. You might spray a preventative fungicide at this point, as well. Follow all manufacture’s recommendations carefully. If you anticipate another freeze in your area, you can lay evergreen boughs or straw over your newly-cleaned out Iris beds for added protection until the spring temperatures return in earnest. At which time, you will remove any covering. Remember, rhizomes grow close to the surface and want to feel that sunshine. Bearded Iris can be very forgiving, largely due to their very sturdy nature.

Bulbs vs. RhizomesDenseClump-web

Just a short two bits on the distinction between two of the methods herbaceous perennials (including Bearded Iris) utilize for food storage…. Plants have evolved several methods of storing food so that they can spring to life when the conditions are right, bulbs and rhizomes among them. The definition of a bulb is any plant that stores its complete life cycle in an underground storage structure. The “food” is converted sunshine, collected through the leaves through photosynthesis, and carried into the “larder”. Only some of the plants commonly called bulbs actually are bulbs. Bearded Iris, although falling into the above definition, develop a storage structure known as a rhizome (really an underground “stem”). The rhizome is the larder for nutrients that give the plant the energy it needs to grow, bloom, and complete its life cycle. Trimming the Iris foliage too early deprives the plant of its food intake.  Rhizomes grow horizontally just under the surface of the soil which is why they must be planted shallowly, in soil with good drainage.

Peggy Sue with Lilies and Echinacea

Send Iris the promise of Iris…with our annual Sweetheart Iris Collection!

Celebrate the passion of Valentine’s Day all over again during Iris bloom season. Send these five radiant Tall Bearded Iris to your sweetheart, or invite them into your own heart (and garden)* with our annual  Sweetheart Iris Collection.
These five sweet beauties offer wonderful discount and a lovely array of pink, just screaming out, “Be Mine!”

Only $49.95 (plus s/h)

(*We ship our freshly dug Iris July – September)

Thank you to the following websites for the succinct information on bulbs and herbaceous perennials: and