Bright, clear sunshine lit the streets this morning, making the morning commute feel somewhat tolerable to caffeine deprived brain cells.

My daughter and I marveled at the depth of color swirling underfoot, as falling foliage transformed normally subdued streets and sidewalks into glistening streams of overlapping garner, tangerine and butterscotch.

But as we rounded a corner on the main thoroughfare to school, a wall of thick fog appeared out of nowhere and suddenly it became a stretch to see much of anything. No sunlight and certainly no color, except for the flash of scarlet from vehicle brake lights immediately ahead of us.

It reminded me that in late autumn, all expectations are up for grabs. A stormy morning can morph into a glorious afternoon within minutes. Fog can drop down from the surrounding hills with little warning, while brisk winds can keep even the sunniest days downright nippy.

Understanding that autumn weather is, well, variable is an important concept for those of us living and gardening in Western Oregon. I tend to fight an especially tight time line when it comes to end-of-season plant division. I invariably wait until the weather abruptly changes for the worse. And then I'm trudging out into the freezing rain, garden forks and sharp knives at the ready, miserably whacking plants into pieces.

Aurgh! I never learn. Fortunately, one great truth about the Pacific Northwest is that we almost always get winter weather breaks: days when the sun reappears, temperatures rise and being outdoors is suddenly enjoyable again.

These golden opportunities for hiking, biking or gardening may last an hour, half a day or longer. But they're often long enough to get at least a few items knocked off that gardening "to do" list.

Dividing old, woody plants is a task that tops many a gardener's list of autumn chores. The soil is still workable and not yet freezing cold, which means that new divisions have time to develop and become established before next summer's heat hits. In addition, it's often much easier in autumn to determine where to dig and how to divide - plants are at a point in their growth cycle where the difference between newer growth and older, woody material is clear.

Unsure which perennial plants are ready for division? Savvygardener.com has a great chart that outlines the basic division needs of many popular perennials (www.savvygardener.com/Features/when_to_didvide_perennials.html - and yes, divide is misspelled in the link; the correct spelling doesn't work).

And here's a revision of division basics that I first discussed back in 2001. Happy grubbing!

n Plants that may need division every two to three years: Bearded iris, delphinium, phlox, aster, monarda, achillea millefolium, centranthus, crocosmia 'Lucifer,' coreopsis, geum hybrids, dianthus.

n Plants that may need division every four to five years: Ameria, achillea 'Coronation Gold,' astrantia major, geranium 'Johnson's Blue,' lamium, rudbeckia 'Goldsturm,' liatris spicata, stachys byzantina (lamb's ear), veronica, hemerocallis.

n Plants that may need division every six to 10 years: alchemilla mollis, brunnera macrophylla, echinops, sedum 'Autumn Joy', ruta gravens, verbascum, filipendula, asarum europaeum,, ligularia dentata, polygonatum odoratum 'Variegatum,' kniphofia.

n Plants that may need division every 10 years or more: Helleborus orientalis, hibiscus, hosta, aquilegia hybrids, cimicifuga racemosa, paeonia hybrids, perovskia.