Waiting for Rain on the West Coast

by Kathleen Sayce 

The astronomical calendar has rotated into autumn: Rain and cooler weather bring mushrooms, migrating birds and salmon, and new growth for many types of irises.  Here on the West Coast, it’s time to plan fall lifting, dividing, and replanting of Pacifica irises.

Wait for your plants to show fresh white roots that are at least two inches long. If you have access to irrigation water, water thoroughly a few times in September and October to help encourage Pacifica irises to break summer dormancy. Watering is needed only when replanting, and not weekly thereafter (unless it doesn’t rain for weeks and the soil dries out). 

Monitor weather for rain, and wait for the soil to dampen to a depth of at least six inches (or irrigate your garden). When new iris roots emerge, start planning times to rework and plant flower beds. Better yet, consider scheduling a planting party! Along the coast, this is usually October into November. 

Take time to replenish soil coverings (aka mulches), and amend soils with nutrients and carboniferous materials like compost, ramial, and biochar. Any time you dig a plant hole, add some carbon, work it into the hole, and then replant. My preferred carbon-rich materials and sequence (bottom to top) are: biochar, compost, ramial, wood chips. 

Although I make my own compost, I never have enough. Ants, mice and voles haul seeds around, and seem to like dragging grass seeds and some dicots into my compost piles. If you can get it, compost from methane digesters is seed free. 

When I rework beds, I layer biochar and compost over the open garden bed that is ready to replant. Then I plant into this area, working the carbon materials down and around each hole and the roots. I may also add more compost on top, below the top layers (ramial and wood chips). 

Ramial is a freshly shredded blend of hardwood stems and leaves, like shrub and tree branches. During fall cleanup I shred hardwood branches before leaf fall, and put these chips out as a top dressing on garden beds. This mix breaks down easily without needing extra nitrogen, and helps boost carbon in the soil. It’s almost as good as foliar sprays for plant health. Like compost, I never have enough ramial. 

Biochar is charcoal, pretreated with compost to inoculate it with microorganisms, and is usually ground into a coarse powder. It helps soils retain water and nutrients, and promotes good soil structure. It’s especially a boost for beneficial soil fungi, which helps promote healthy roots in Pacifica iris.

Perennials thrive with wood chip mulches. We have trees, which regularly need limbs removed. I chip them, and turn the resulting wood chip pile to compost. Fungal mycelia appear throughout the wood piles within a few weeks. When I add these chips to an iris bed, fungi are coming with them. Fungi are beneficial for both the soil and my plants. 

If wood chips are too coarse when fresh, run them through a chipper.  (NOTE: I have learned the hard way to wear a mask when chipping—my lungs do not care to inhale wood dust, fine bits of leaves, shredded fungi, or compost fragments. For extra protection, put a bandana over the top of a N95 mask. Eye protection is a good idea too.)

Fine wood chips can also be added to a compost pile. They provide a coarse source of carbon and help break down food scraps for optimal compost texture.

Other soil amendments to add to garden soils during the fall include: eelgrass, dried kelp meal, ground oyster shells, feather meal, and mineral soil amendments. 

Eelgrass mats wash up on the boat ramp at the local port, which gardeners can collect. We have enough rain that we can add it to garden beds, on top of the wood chips, and know the rain will dilute the salt. Otherwise, lay the eelgrass out to compost, let rain wash the pile for a month or two, then spread it.

Winter is coming, but before that season comes fall--the best time to plant, replant and transplant on the West Coast. Enjoy the season!

Perils of Procrastination among Pacifica Iris

Kathleen Sayce
March 29, 2016

For those perfect gardeners among us, no pot of Iris seedlings ever goes a year or two too long before being separated and planted out. 

I'd like to know who they are, because this year I learned what happens when a styrofoam box of Pacifica Iris seedlings grows a year too long before division:  They grow their new roots into the box walls, out the bottom and into whatever medium is beneath. If the potting mix is to their liking, they also completely fill the mix with roots. 

A year past optimal planting out size, this dense mass of Pacifica Iris seedlings was not about to move to a new home easily. 

Thus, there I was on a sunny early spring day between storms, prying plants formerly seen as fragile out of what was formerly a porous and well drained potting mix of coarse perlite and half potting soil.  

First I tugged, then I tried to dig out some of the medium and gain some working space.  A few frustrating minutes followed with very little movement towards releasing these irises from their starter home. 

Sign of a thriving patch of Iris seedlings:  roots through the box into the gravel beneath. 

Then I resorted to my new favorite tool, a Japanese hori nori (gardening knife) and used the serrated edge to cut between plants, knowing I would cut through some.  Then I got tough, and held the box down with one foot and pried with both hands. Finally, most of the soil and roots emerged in a solid mass, which I was able to cut, not pry, apart. 

On the second box, I simply cut it open along the corners and took the mass of roots and plants out, and then cut them apart. 

Remains of the planting box to the left, a portion of the root mass to the right

Then I checked the plants from last year, which will go out soon, and sure enough, these young Pacifica Iris have also grown through the box into the ground and into the walls. Only a third the size of the older seedlings, they should come out a little more easily. . . 

Last year's seedlings are also ready to go, but I might not need to stand on my head to get these out, if I move them soon. 

There are undoubtedly some choice seedlings buried in the masses I planted––which is probably the worst of the unintended consequences. 

Why use styrofoam boxes for seeds? In the first few years of growing irises from seed, I found that dark plastic pots heat up in the summer, and when combined with normal summer drought, many seedlings died. I grow larger seedlings faster in styrofoam, which I deduce keeps the roots cooler. I may need to rethink the larger-faster-healthier choice and go back to slower, smaller and a little less vigorous. Or get out in the garden and repot them more promptly!

Lifting, Dividing, and Transplanting Pacifica Iris

Kathleen Sayce

The seasonal forecast for the Pacific Northwest was for a mild, warm, drier-than-normal fall. Hmm. Warm, yes; dry, no. So far we've had a series of storms blow through, each one dropping around two inches of rain. For dry gardens (those that do not get additional irrigation water), this means that Pacifica Iris began putting out new roots a few weeks ago. New white roots means that these plants can be dug up and transplanted. 

'Premonition of Spring' in flower between storms; the flowers aren't perfect due to the weather and slugs, but provide a cheerful corner in the garden during winter. 

Pacifica Iris are notoriously fussy about being moved, particularly in climates with prolonged dry summers. I've mentioned before that checking the roots to make sure that there are 1-4 inch long white (live) roots is important for success. 

New roots on Pacifica Iris fans show that this plant is in active growth and can be moved. 

Today I went out between showers (the thunder, lightning and hail type of showers) to redo a densely overgrown patch of PCI seedlings. Let's not go into why I did not do this two or three years ago. As gardeners know, life often gets in the way of garden plans and ideal timing for gardening activities. 

There are five different irises in this patch:  four seedlings, one of which has not yet flowered, and one named variety. 

What a little procrastination can give you:  a near-solid mass of irises to separate and divide. If I'd waited another year, it might have been near-impossible to divide out the different seedlings. Spuria iris on the lower right (its long leaves were broken down in the last storm), 'Premonition of Spring' on the left, next to the cyclamen, and in the middle, three massively overgrown PCI seedlings. 

One of the seedlings is not going back into the garden. It came to me as orange-flowered I. innominata seed; by the second year it was clear that this seedling is really a Spuria Iris. So it's going south to Los Angeles, to a much warmer climate where it might actually flower.

The clue that this clump is not a Pacifica Iris:  the leaves were three to four times as tall as the other irises around it!

Pacifica Iris clump in the middle, Spuria clumps on the right with their leaves already partially cut back. 

Three of the seedlings are from open pollinated seeds from Debby Cole's garden on Mercer Island, Washington; the pod parent is her vivid PCI hybrid 'Egocentric'. I'm still evaluating the lavender flowered seedlings; the yellow seedling is a nice sturdy plant, and I'm sending starts to other gardens.

One of the lavender-flowered PCIs from an 'Ecocentric' pod parent seed lot. 

Another seedling from the same seed lot; sturdy short plant, waiting to see the flowers for one more season before I decide to keep or toss. 

A yellow flowered Pacifica seedling, pod parent, I. 'Egocentric', from Debby Cole.  This one I will keep. The plant is sturdy, the flowers are held well above the foliage, and are well shaped. 

The fifth iris clump in this patch is 'Premonition of Spring', Garry Knipe's winter flowering selection.  I divided this one into two smaller masses and replanted one near the other. Like Iris unguicularis, it flowers sporadically from fall through early spring. In fact, both clumps (POS and I. unguicularis) have buds or flowers right now, and will flower occasionally during fall-winter-spring months. I plan to move an I. unguicularis clump nearby. 

Once each clump is out of the ground, I use clippers to cut apart the fans. Sturdy rhizomes grow between groups of fans, and my hand clippers easily cut through them. 

A nice pile of more than one dozen fans are going to other gardens. 

After replanting, the plants have room. Next spring I'll be able to see the flowers on each plant more easily, evaluate them, and decide which seedlings to keep. I also found two mesh bags with seeds inside––these are going to be scattered in a patch of native grasses to naturalize.

Lifted, divided, and replanted, and ready to grow on this fall and into next spring.

I was done just in time to avoid the next shower!