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Flag this! Dig and divide now for more flowers next spring


These are Debbie Arrington's heirloom blue flag irises.
(Photo: Debbie Arrington)
Did your bearded irises stop blooming? They likely need late summer rejuvenation



By dividing, these plants multiply.

Bearded irises rank among the best-flowering perennials for the Sacramento garden. They’re low maintenance, drought tolerant and reliable. They pretty much take care of themselves most of the year, dying back in fall before re-emerging for a massive spring flower show (and sometimes more in fall).

But every three to five years, bearded irises need to be dug up and started over. That’s the key to their durability and consistent bloom.

If a bearded iris in your yard has stopped blooming, it most likely needs to be divided. In the end, you get more plants – and more flowers.

Timing is everything with this chore; irises need to be divided and replanted in late August or September to get ready for winter dormancy. So now is the right time to dig up the iris bed.

Bearded irises grow from rhizomes, fat segmented tubers that grow just under the soil. Over time, the rhizomes lose their vitality. They rot or wither away. Side shoots grow from the central rhizome to form new baby rhizomes. It’s those baby rhizomes that will produce the future blooms.

Each rhizome produces thumblike protrusions with fans of leaves attached. Once a “thumb” produces a flower stalk, it won’t bloom again. So, any segments attached to flower stalks should be discarded, allowing room for the other “thumbs” to grow.

How do you know which to keep, which to cut? Dig up the rhizomes and look.

Shallow-rooted, they come up very easily, pried from the ground with a pitchfork or spade. (Be careful not to whack the rhizome you intend to keep.)

Once they're unearthed, wash off the rhizomes with water and start working them apart, using your fingers and a trowel or sharp knife. Keep the young, healthy rhizomes with one or two fans of leaves and healthy roots attached. Break off the aged, bloomed-out, rotted or dried-out pieces and discard. Also look for insect damage; cut that out, too.

Now, you’re ready to replant. First, rejuvenate the planting area with some well-aged compost and a little bone meal, worked into the top 6 inches of soil. On the irises, trim the leaves down to 4 to 6 inches.

Plant the rhizomes about 12 inches apart so the fan of leaves sits right on the soil surface, with the rhizome just under the soil. Unlike most perennials, don’t cover these with mulch. (That can promote rhizome rot.) Water deeply once, then let rest.

The irises will take over from there.

This method will keep a clump of bearded irises blooming and healthy for generations. I know. With unusually tall and fragrant flowers, this clump of old-fashioned blue flags originally came from my great-grandparents’ farm. Growing in the same spot for 70 years, it gets dug up and replanted every five years or so. And it’s still blooming strong.

A little extra effort two or three times a decade pays off.

Want to learn more about irises? Check out the Sacramento Iris Society:
https://sacramentoirissocietydotcom.wordpress.com/

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Garden checklist for week of April 19

After this midweek storm, start getting serious about spring gardening. Flowers are blooming about three weeks ahead of schedule. That includes weeds!

* Get ready to swing into action in the vegetable garden – if you haven’t already. As nights warm up over 50 degrees, set out tomato, pepper and eggplant transplants.

* From seed, plant beans, beets, cantaloupes, carrots, corn, cucumbers, melons,  radishes and squash; wait on pumpkins until May. Plant onion sets.

* In the flower garden, plant seeds for asters, cosmos, celosia, marigolds, salvia, sunflowers and zinnias. Transplant petunias, zinnias, geraniums and other summer bloomers.

* Plant perennials and dahlia tubers for summer bloom. Late April is about the last chance to plant summer bulbs, such as gladiolus and tuberous begonias.

* Transplant lettuce and cabbage seedlings.

* April is the last chance to plant citrus trees such as dwarf orange, lemon and kumquat. These trees also look good in landscaping and provide fresh fruit in winter.

* Smell orange blossoms? Give citrus trees a low dose of balanced fertilizer (such as 10-10-10) during bloom to help set fruit. Keep an eye out for ants. If leaves look yellow, your tree may need an iron boost -- apply some chelated iron fertilizer.

* Apply slow-release fertilizer to the lawn.

* Thoroughly clean debris from the bottom of outdoor ponds or fountains.

* Spring brings a flush of rapid growth, and that means your garden needs nutrition. Give shrubs and trees a slow-release fertilizer. Mulch with a 1-inch layer of compost, which helps the soil, but keep it a few inches away from trunks and stems.

* Azaleas and camellias looking a little yellow? If leaves are turning yellow between the veins, give them a boost with chelated iron.

* Trim dead flowers but not leaves from spring-flowering bulbs such as daffodils and tulips. Those leaves gather energy to create next year's flowers. Also, give the bulbs a fertilizer boost after bloom.

* Pinch chrysanthemums back to 12 inches for fall flowers. Cut old stems to the ground.

* Mulch around plants to conserve moisture and control weeds.

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Food in My Back Yard (FIMBY) Series

Lessons learned during a year of edible gardening

WINTER

Is edible gardening possible indoors?

Hints for choosing tomato seeds

Starting in seed starting

Why winter is the perfect time to plant fruit trees

When to plant? Consider staggering your transplants

How to squeeze more food into less space

Potatoes from the garden

Plant a fruit tree now -- for later

Win the weed war by tackling them in winter

Tips for planting bare-root trees, shrubs and vegetables

Time to give vegetable seedlings some more space

Ways to win the fight against weeds

FALL

Dec. 16: Add asparagus to your edible garden

Dec. 9: Soggy soil and what to do about it

Dec. 2: Plant artichokes now; enjoy for years to come

Nov. 25: It's late November, and your peach tree needs spraying

Nov. 18: What to do with all those fallen leaves?

Nov. 11: Prepare now for colder weather in the edible garden

Nov. 4: Plant a pea patch for you and your garden

Oct. 27: As citrus season begins, advice for backyard growers

Oct. 20: Change is in the autumn air 

Oct. 13: We don't talk (enough) about beets

Oct. 6: Fava beans do double duty

Sept. 30: Seeds or transplants for cool-season veggies?

Sept. 23: How to prolong the fall tomato harvest 

SUMMER

Sept. 16: Time to shut it down? 

Sept. 9: How to get the most out of your pumpkin patch

Sept. 2: Summer-to-fall transition time for evaluation, planning

Aug. 26: To pick or not to pick those tomatoes?

Aug. 19: Put worms to work for you

Aug. 12: Grow food while saving water

Aug. 5: Enhance your food with edible flowers

July 29: Why won't my tomatoes turn red?

July 22: A squash plant has mosaic virus, and it's not pretty

July 15: Does this plant need water?

July 8: Tear out that sad plant or baby it? Midsummer decisions

July 1: How to grow summer salad greens

June 24:  Weird stuff that's perfectly normal

SPRING

June 17: Help pollinators help your garden

June 10: Battling early-season tomato pests

June 3: Make your own compost

May 27: Where are the bees when you need them?

May 20: How to help tomatoes thrive on hot days

May 13: Your plants can tell you more than any calendar can

May 6: Maintain soil moisture with mulch for garden success

April 29: What's (already) wrong with my tomato plants?

April 22: Should you stock up on fertilizer? (Yes!)

April 15: Grow culinary herbs in containers

April 8: When to plant summer vegetables

April 1: Don't be fooled by these garden myths

March 25: Fertilizer tips: How to 'feed' your vegetables for healthy growth