IndigoTiger, yes, those Marcy Tilton checked and plaid taffetas are very Krista Larson for her silk clothing. She also does the same styles in simple cotton prints, cotton stripes, eyelets, and plain linens.
Cindy, here’s a stab at a definition of lagenlook.
Often three or more visible layers (that is, not counting underwear).
Loose fit, ranging from a bit loose to oversized, depending on taste. This is generally a total look, not a combination of loose and closely fitted garments.
Natural fibers. Linen and cotton are very popular in warm climates, woolens are very popular in cool climates, and silk is used in both climates for fancier garments.
No specific colors are associated with lagenlook. The tailored look (see below) favors plain fabrics (that is, no prints, stripes, or the like). In addition to plain colors, the frilly look favors traditional-looking cotton prints, eyelets, stripes, checks, and plaids. Woolens are often heathered.
Two main looks: Tailored and frilly/Edwardianish. The difference between the two can be putting (or not putting) a ruffle (or ruffles) on the same garment. For many examples of the tailored look from different manufacturers, see the eBay store Watersister (aside from some ugly jewelry) and the designer Cynthia Ashby, among others. For the frilly look, among others see the designers Krista Larson, Ivey Abitz, Tina Givens, Sarah Clemens, Magnolia Pearl, and Ewa i Walla. German and Scandinavian lagenlook often has a folkloric air, including scoop-necked peasant vests and multicolored embroidery.
Popular garments include tunics (varying from hip length to almost floor length), loose crop tops (that is somewhere above the waist), loose vests, long skirts and dresses, and wide and balloon pants. The frillier look often features jumpers, and petticoat-skirts and drawer-pants peeking below jumpers, dresses, or tunics. Outerwear includes long loose coats, long sweaters, and although as not often shown with lagenlook I think ponchos are ideal. There is no standard hemline length for any garment.
Especially for the tailored look, details include what I call random piecing (a garment section that doesn’t really have to be cut separately, and which can be a contrasting fabric or not). Also for both the tailored and frilly looks, irregular tucks, uneven hems, and drawstring effects are popular.
Hats: They are not often shown with American lagenlook, but the Germans like woolly hats, knitted or fabric.
Jewelry: I’ve never seen much discussion of this, but I think handmade-looking, informal-looking jewelry works best.
Pattern sources: Vogue, Butterick, McCall’s, Simplicity, Tina Givens (though her sizing is often strange), Tessuti, Folkwear, some Japanese pattern books, and a book titled Bold & Beautiful Easy-Sew Clothes.
Interestingly, lagenlook is not primarily a handmade look. Not only is most of it commercially made, it does not focus much on hand embroidery, hand knitting, fancy dyed effects, stenciling, or any other kind of handmade decoration or handwork, whether the real thing or machine imitation. However, the simple styles lend themselves very well to handwork. Lace trim is not that popular either, even with the frilly/Edwardian look. An exception is Magnolia Pearl.
Although anyone can wear lagenlook, I often feel the target markets are women over 50 and women of any age who are a bit overweight. Some women over 50, including me, like lagenlook for its echoes of the Edwardianish styles of the 1970s and 1980s and its somewhat (or even very) bohemian air.