The Whole “Scoop” on Fertilizing Iris

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

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: www.ces.ncsu.edu and https://www.growingagreenerworld.com

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Start the Season with Early Blooming Iris

Dwarf iris can be seen blooming among the tulips, weather depending.

Easy to plant, easy to care for, easy to enjoy! That is the Iris. And such variety too! Variety of size, variety of bloom season, variety of color, variety of style. Isn’t success in life all about the choices we make? That simple maxim can apply to the realm of the flower garden too. The Iris offer such a host of choices, one is surely to find just the right color, or size, etc. Let’s talk about the breadth of bloom time, for example. The Miniature Dwarf Iris and the Standard Dwarf Iris are among the very first Iris to bloom. Weather depending, of course, they open up their diminutive blossoms (just 5 to 15 inches in height) approximately mid-March to early April (in most temperate zones), heralding the launch of another promising Iris season.

The Dwarf Bearded Iris are no less hardy than their taller, more robust cousins. Dwarf Iris, both Miniature and Standard types, propagate with strength and, once in bloom, stand up to the early spring frosts. There are several wonderful resources available which provide great detail on the origins of these hybrids. The Dwarf Iris Society is a good place to start for further links and leads on exploring the subject. Several Iris breeders today have introduced spectacular Bearded Iris cultivars in miniature.

Intermediate Iris bloom early in the spring, often alongside tulips

As spring widens its embrace upon the land, weep not for the fading Dwarf Iris, for the Intermediate, Median, or Border Iris are opening on the garden scene! A bit taller than the tallest Dwarf, yet shorter than the shortest Tall Bearded Iris, they offer brilliant bloom to span the gap between March and May, a beautiful complement to the Cherry blossoms! The earliest blooming Tall Bearded Iris will overlap with the later-blooming Intermediate Iris, to create a seamless floral transition of color. Sprinkle in several mid-season and late-season Tall Bearded Iris around your garden, and the color show continues well into June.

A few moments spent casually mapping out the succession of Iris blooms in your garden will yield months of rainbow color from your ankles to above your hips! Dwarf, Intermediate, Tall Bearded, as well as Beardless Iris, are all planted in the summer months. Below is a simple chart, indicating approximate bloom times for Iris ranging from the Miniature Dwarf to the Tall Bearded, and including the Beardless Iris such as, Siberian and Louisiana. Bloom time is greatly dependent on weather conditions and gardening practices, however. For example, Reblooming Iris require regular extra fertilization, watering and dividing.

March	April	May	June	July/Aug/Sept/Oct
Min. Dwf. & Std. Dwf. (5″ to 15″; 5cm to 28cm)	Intermediates & Border (16″ to 27″; 40cm to 68cm)	Tall Bearded (28″ to 48″;70cm to 122cm)	Tall Bearded & Beardless (such as, Siberian and Louisiana)	Reblooming Bearded Iris of all sizes

Intermediate Iris (IB) “Many Mahalos” (Aitken, 2003) blooms early, among the tulips.

If you are one who can hardly wait for the year’s Iris season to start, you have merely to plant some Dwarf Bearded Iris this summer. You will have Iris blooming with the first inkling of spring warmth. Even if you consider yourself simply a fan, a dabbler, a curious gardening newbie to the world of flowers, give the Dwarf Iris a try!

Do you grow Dwarf Iris? Share your comments below!

What to do in the Iris garden this month…..read more on our site.

Consider the Early Blooming Iris

Standard Dwarf Bearded Iris, Heather Carpet (Chapman, 1999), hugs  a garden path.

Easy to plant, easy to care for, easy to enjoy! That is the Iris. And such variety too! Variety of size, variety of bloom season, variety of color, variety of style. Isn’t success in life all about the choices we make? That simple maxim can apply to the realm of the flower garden too. The Iris offer such a host of choices, one is surely to find just the right color, or size, etc. Let’s talk about the breadth of bloom time, for example. The Miniature Dwarf Iris and the Standard Dwarf Iris are among the very first Iris to bloom. Weather depending, of course, they open up their diminutive blossoms, just 5 to 15 inches in height, approximately mid-March to early April (in most temperate zones), heralding the launch of another promising Iris season.

Intermediate and Border Bearded Iris blooming at Schreiner’s Iris Gardens

Weep not for the fading Dwarf Iris! For the Intermediate, Median, or Border Iris are opening on the garden scene. A bit taller than the tallest Dwarf, yet shorter than the shortest Tall Bearded Iris, they offer brilliant bloom to span the gap between March and May, a beautiful complement to the Cherry blossoms! The earliest blooming Tall Bearded Iris will overlap with the later-blooming Intermediate Iris, to create a seamless floral transition of color. Sprinkle in several mid-season and late-season Tall Bearded Iris around your garden, and the color show continues well into June.

Let’s have a few more words about these Dwarf Iris, though. The Hungarian language has a saying, “The pepper corn is small, but mighty.” (Kicsi a bors, de erős.) The same can be said about these Iris of smaller stature. They are no less hardy than their taller, more robust cousins. Dwarf Iris, both Miniature and Standard types, propagate with strength and, once in bloom, stand up to the early spring frosts. There are several wonderful resources available which provide great detail on the origins of these hybrids (quite fascinating, really). The Dwarf Iris Society is a good place to start for further links and leads on exploring the subject. Several Iris breeders today have introduced spectacular Bearded Iris cultivars in miniature.

A few moments spent even casually mapping out the succession of Iris blooms in your garden will yield months of rainbow color from your ankles to above your hips! Dwarf, Intermediate, Tall Bearded, as well as Beardless Iris, are all planted in the summer months. Below is a simple chart, indicating approximate bloom times for Iris ranging from the Miniature Dwarf to the Tall Bearded, and including the Beardless Iris such as Siberian and Louisiana. Bloom time is greatly dependent on weather conditions and gardening practices, however. For example, Reblooming Iris require regular fertilization and dividing.

March	April	May	June	July/Aug/Sept/Oct
Min. Dwf. & Std. Dwf. (5″ to 15″; 5cm to 28cm)	Intermediates & Border (16″ to 27″; 40cm to 68cm)	Tall Bearded (28″ to 48″;70cm to 122cm)	Tall Bearded & Beardless	Reblooming Bearded Iris of all sizes

Music, Standard Dwarf Bearded
Keith Keppel, 1999

As Barbara Whitehouse and Bee Warburton write in their chapter entitled “Miniature Dwarf Beardeds”, in The World of Irises, (The American Iris Society, 1986) “…each iris lover should grow at least one or two clumps of them …. However, they are so charming that one or two clumps may ultimately become a whole bed or border.” (pg 145)….

If you are one who can hardly wait for the year’s Iris season to start, you have merely to plant some Dwarf Bearded Iris this summer. You will have Iris blooming with the first inkling of spring warmth. Even if you consider yourself simply a fan, a dabbler, a curious gardening newbie to the world of flowers, give the Dwarf Iris a try!

Do you grow Dwarf Iris? Share your comments below!

What to do in the Iris garden this month…..read more on our site.

Bearded Iris Grow Strong All Summer Long

Summer days, summer gardens. Most enjoyable. For the Tall Bearded Iris in your garden, summer is also the perfect time to grow, to expand, to be transplanted.

Bearded Iris experience two root growth cycles in their annual growing cycle. The springtime growth we all eagerly anticipate in our Iris beds begins with the lengthening of the foliage upward and the root system outward. The rhizome uses its stored-up nutrients.”….As the bud swellings appear in the new fans there is a quickening of the new roots that will supply the plant with nutrients for new growth during and after bloom. The old roots from the previous year’s growth then wither and decay.” ( The World of Irises, p 314)  After the springtime color display of full bloom has passed for the year, the underground development begins in earnest.

The Iris revel in the long summer days. During the six to eight weeks post bloom, the plants absorb the necessary nutrients for next spring’s growth and bloom. The rhizomes send out new increases which will become new self-contained, self-supporting rhizomes by early to mid-July. Once the summer growth is complete, the Iris takes a well-earned rest. Enter the gardener, spade in hand, plan in mind. Now is the time to dig, divide, share and transplant.

Here, in the Willamette Valley our Iris bloom season ends early- to mid-June. Therefore, at Schreiner’s Iris Gardens, we begin digging our fields early to mid-July. On a smaller scale in your garden, consider digging your Iris to transplant this summer if the clump is three to five years old. Share the divided Iris not only in your own garden, but also with the neighbors, friends and family….garden clubs, retirement homes, 4H clubs, and so on. Allowing Iris clumps to become over grown can lead to poor or no blossoms, smaller and smaller rhizomes, and outbreaks of rhizome-based diseases (such as bacterial soft rot).

Remember that the latest date for transplanting depends on local conditions. Newly planted Iris require a minimum of 6 weeks to set their new roots. Thus, they should be in the ground a minimum of six weeks before the first hard frost. Consult local resources to determine the frost dates in your area.

So, how do you go about digging and dividing the Iris in your garden? Visit our “How to Grow Iris” pages for more details and images on dividing and caring for your Iris! Take a look at another great Iris care resource, “A Guide to Bearded Irises: Cultivating the Rainbow“, by Kelly D. Norris.

What’s happening in the July garden? To trim or not to trim the foliage…Depending on your location, you may have a handful of lingering Iris blossoms, or all of your bloom stalks might be sporting the papery remains of the seasons’ blooms. When all blossoms on the stalks have finished, carefully trim the bloom stalk at its base. Leave all green foliage, though, in place. They offer an elegant vertical visual throughout the garden. You may remove any browned and dry leaves. Keep the Iris beds clean and free of weeds. Well-established Iris plants are drought tolerant. Newly planted Iris, though, do require a good long drink approximately every 7 to 10 days if the weather is very dry. Reblooming Iris also prefer irrigation between the spring bloom and summer/autumn re-bloom times. We recommend an application of a low-nitrogen fertilizer (such as 6-10-10) approximately one month after blooms have finished. Superphosphate and bonemeal also work well as a fertilizer for Iris.

Summer brings the promise of long days enjoying our gardens and all aspects of our lives. The season also brings with it our annual Summer Sale. You’ll find over 300 varieties of Tall Bearded Iris at deeply discounted prices.

June Has Busted, June Has Burst! Quench Your Tall Bearded Iris Thirst!

The summer solstice, a most propitious date — brings the promise of long, heady days of summer, reaping the success in our gardens and in all aspects of our lives. June 21st also heralds the start of our 2014 Summer Sale. You’ll find over 350 varieties of Tall Bearded Iris at deeply discounted prices. Pictured on the cover of our summer sale catalog below is a special bonus for your summer sale order. “Swept Off My Feet”, one of our 2014 introductions, is the 2014 Summer Sale bonus. Use coupon code SSC2014 to get yours. (*Limit one per customer; minimum $25 order of plants.)

What’s happening in the June garden? Depending on your location, you may have a handful of lingering Iris blossoms, or all of your bloom stalks might be sporting the papery remains of the seasons’ blooms. When all blossoms on the stalks have finished, carefully trim the bloom stalk at its base. Leave all green foliage in place. They offer an elegant vertical visual throughout the garden. You may remove any browned and dry leaves, though. Keep the Iris beds clean and free of weeds. Well-established Iris plants are drought tolerant. Newly planted Iris, though, do require a good long drink approximately every 7 to 10 days if the weather is very dry. Reblooming Iris also prefer irrigation between the spring bloom and summer/autumn re-bloom times. We recommend an application of a low-nitrogen fertilizer (such as 6-10-10) approximately one month after blooms have finished. Superphosphate and bonemeal also work well as a fertilizer for Iris.

Saving Overgrown Iris

Nature happens….

Let’s say a friend told you about this patch of once-lovely Iris which has become completely engulfed by grass… (or maybe that friend is you…) You tell your “friend” that her situation reminds you of something you once read by Sara Stein*: “I appreciate the misunderstanding I have had with Nature over my perennial border. I think it is a flower garden; she thinks it is a meadow lacking grass, and tries to correct the error.”

July, August and, in some areas, September, is the time to assess the situation in your Bearded Iris garden, and rectify the misunderstanding you might have with Nature. If it’s been a few years (say three to five) since you planted your Iris, it is likely that the clusters have grown, and over-grown, themselves into a large mass of rhizomes 12 to 24 inches wide. If you are (or know of) that friend described above, fear not. If you see foliage above the blanket of grass, the Iris can be saved! Read on.

Before you reach for the shovel, though, let’s review some tips on dividing and transplanting the new Iris babies.

Iris Identity: If you have your Iris labeled, you will want to label all of its babies. Prepare tags of some sort to help you keep track of what you are transplanting and where. If you haven’t labeled the Iris in your garden, then proceed unfettered by the bondage of labels….

Digging the clumps: Depending on how densely packed the Iris clump is, you may wish to dig up the entire mass and work on it out of the ground. In the case of the clumps overgrown with grass, you’re best bet is to dig up the whole shebang. Carefully pull the soil and grass away from the rhizomes and roots so that you can see what you’re dealing with. Take care to remove as many of the grass roots as possible. Once cleaned up, you will likely find that the mass of Iris resembles a tangle of fresh ginger, or small oblong potatoes, some of which will have fresh green foliage attached.

New growth on left and right of spent rhizome

Separating the plants: The rhizomes with the foliage are the plants you will keep. Any rhizome which has no foliage is “spent”, and will not bloom again. It can be discarded. At this point, you can decide how many of these new plants you’d like to replant. Some of the new growth may yet be quite small, the size of a cherry. These are called “nubs”, and will have tiny green leaves. You can plant these, but expect possibly two years at least before you see any blooms.

To separate, carefully snap or slice the rhizomes at the junction between the old plant and the new growth. Take care to disentangle the roots so that the new plants retain their set of roots.

Cut or break off new growth from original rhizome

If the foliage on the new plant is very tall, you can trim it back to 6 inches to make transplanting easier.

Prepare soil for transplants: For the area where you intend to plant the new growth, dig up the soil 6 to 12 inches deep, remove weed sprouts, mix in some organic mulch or a low-nitrogen fertilizer (follow manufacturer’s recommendations for quantity and ratio) to give the soil a nutritional boost. Break up large clumps of soil and smooth out the area. Plant your new iris so that the roots are covered but the top of the rhizome is showing above the surface of the soil.

Water in: Water at the time of transplanting. Newly set plants need moisture to help their root systems become established. Specific watering requirements depend on your climate and soil, but keep in mind that deep watering at long intervals is better than more frequent, shallow watering. Once established, Iris normally don’t need to be watered except in arid areas. It is always better to underwater than over water. Too much water can induce rot.

What to do if you have more Iris shoots than you know what to do with: Consider donating the extra plants (labeled or unlabeled) to a nursing home, school, or community center in your area. You can also check with your neighbors to see if they’d like any of the offspring.

Getting ready to divide your Iris? Tell us what you do with the extras. We’d love to read your comments.

*Sara Stein, influential advocate for gardening with native plants, and author of “Noah’s Garden: Restoring the Ecology of Our Own Backyards” (Houghton Mifflin, 1993).

Summer Around the Gardens

Day Lilies brighten our summer garden

July – that quintessential “summer” month. This middle month of summer seems to hold an abundance of potential… for projects, vacations, gardening, and camps. Don’t we find ourselves wondering how we could cram more into these 31 days? June is too early, and by August we already feel the end of summer.

July is a busy month around the gardens here as well. We go full-swing into our digging and shipping mode. The buildings are fitted with various conveyor belts for sorting, cleaning, tagging and packing the Iris for delivery to retail and wholesale customers. The fields of Iris, waves of colorful bloom just a month ago, now yield themselves to the crews and diggers. Trucks come and go, loaded with thousands of orders of Iris.

Preparing gardens for replanting

This year is an exciting year for our display garden. We replant our gardens every three to five years. This summer, in preparation for the American Iris Society convention to be held up the road in Portland in May 2015, we will completely replant our 10-acre display garden. Our dedicated, and very hard-working, crew seems to make light work of this tremendous task!

If you are also feeling ambitious and energetic this middle-month of summer, you may also wish to revamp your Iris beds. Perhaps it’s time to divide the older clumps of bearded Iris, expand their colorful glory through replanting the new growth in more sunny corners of the garden – or by sharing them with friends and neighbors to plant in their gardens. Here’s an idea: if you find yourself with an abundance of new growth from your Iris clumps, consider donating them to a nursing home, school, or community center; plant them along the edge of a community garden, or check with your city’s parks and rec department about planting them in your local city park.

Replanted display gardens

Dividing Bearded Iris clumps

We offer detailed and illustrated instructions on thinning and replanting Iris clumps on the “How to Grow & Care for Iris” pages of our website. Take a look at the monthly Iris care guides while you’re there.

Whether planting new Iris or thinning old clumps, you’ll want to have a good fertilizer on hand. Bonemeal and super-phosphate (available at your local garden center) are both good choices. A fertilizer low in nitrogen (5-10-10 or 6-10-10) is also a good option. We offer a one-pound bag of specially formulated Iris food on our website.

Whether choosing to “get ‘er done” or put your feet up for a well-deserved break this July, we wish you a pleasant and memorable summer.

P.S. There’s still time to order for planting Iris this summer. Check out our Summer Sale!

More on Fertilizing Iris and Schreiner’s Controlled Release Iris Food

Thank you to all readers who submitted inquisitive and supportive comments to our first-ever blog post! Some of you requested more information on exactly how to use our Controlled Release Iris Food. Here are a few more details:

Our 1 lb. bag of Iris food covers approximately 20 ft2, at the rate of 1 Tablespoon per rhizome. Sprinkle the dry fertilizer around the plant, taking care to keep granules away from direct contact with plant. After you have applied the fertilizer, water gently to encourage the nutrients to reach the roots. The Iris food that we sell is not intended to be diluted and then applied, however.

Our general rule of thumb on the subject of fertilizing Iris is worth repeating:

Late afternoon, Schreiner’s Display Gardens

one month before bloom season, while the tulips are blooming in your area, apply a low-nitrogen, well-balanced fertilizer, such as Schreiner’s 6-10-10 Controlled Release Iris Food.  A second light application about a month after bloom will reward you with good growth and bloom.

May all your Iris be healthy and your garden strong!

The “Scoop” on Fertilizing Iris

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

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. In late September, 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.

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.

Happy gardening!

Information sourced from: www.ces.ncsu.edu