NEWBERG, Oregon–This was not an ordinary year in my herb garden, nor was it for others nearby who found their gardens this spring flooded by 5 feet of water from a burst dike. The inclement winter weather and record rainfall that extended well into spring wreaked havoc on my outdoor stock plants. I had revamped my rosemary test plot the previous fall with at least thirty-six varieties that I was testing for winterhardiness, growth habit, and flower color. The only rosemaries that survived were three established varieties (‘Arp’, ‘Herb Cottage’, and ‘Golden Rain’) and four newly planted varieties (‘Mt. Vernon’, ‘Ticonderoga’, ‘T. S.’, and ‘Frimley Blue’); the rest died. A late spring thaw and freezing rain decimated most of my upright thyme varieties and almost all of the prostrate or creeping varieties.
I heard very similar reports from many herb growers throughout the Willamette Valley.
Eventually, I realized that the massive destruction of my stock plants gave me more space, which lightened my heart. I cleared away the debris and started over. Now there are fewer thymes in the herb border, but those extra stock plants that have been tortured for the past year or two or three are now out of their one-gallon pots and living the good life in the open ground. I always find it remarkable how much growth a newly planted 4-inch-potted herb or gallon-container plant can put on during the summer. It far surpasses the meager growth of a stock plant that I try to nurse back from winter injury and dieback, which never recovers fully and is usually the first target for a bug attack.
I keep some of my stock plants on a short leash: outside during the summer, back into the greenhouse before frosts. This is true for my collection of lemongrasses (Cymbopogon spp.). Almost everyone is familiar with C. citratus, the culinary ingredient of many Asian dishes. With its great flat leaves–which can inflict fine cuts to unwary hands and arms–it looks like a super bulbous-type clone of a obnoxious clumping weed here called Johnson grass. However, if you ever look underneath its foliage and dig deeper, it has terrific canary yellow roots. Lemongrass thrives in our brief summer heat and, if planted in a rich, moisture-retentive soil, usually triples or quadruples in size, which is great when I get around to slicing and dicing it up for cooking. I try not to use so much in the kitchen that I don’t have enough left of the plant to divide, which is the only way to propagate it. Last year, there was lemongrass seed offered for the first time in the United States. I thought, Great, no more cuts and all the lemongrass I could ever want. Alas, it was too good to be true. The seed was later identified as the East Indian lemongrass (C. flexuosous), which is grown more for tea and its strong oil content than for its culinary use. It never did form the swollen leaf bases as the familiar culinary lemongrass, which is West Indian. Oh well, back to plant division and Band-Aids.
The genus has few pests here, so I have eagerly collected other species that do come from seed. One of my favorites is C. exaltatus. It has a bitter lemon scent, but its thinner leaf blades have a beautiful blue cast and later turn reddish at the ends with the onset of cold temperatures. It is also a much more erect grower (up to 5 feet tall) than common lemongrass, and it “flowers”–in the sense of a grass flowering–reliably every year on long 4- to 5-foot stems. I am surprised that I don’t see it more often used in container plantings for vertical accent. I tried to collect the seed, but I wasn’t sure if I was just gathering chaff. I found out later when I bought some C. flexuosous seed that it does look like chaff and that you sow it with a lot of faith. Recently, palmarosa or rose geranium-scented grass (C. martinii motia) has become available in seed. It, too, is easy to grow (if you don’t mistakenly weed it out). The crushed leaves contain geraniol and do really smell like rose-scented pelargoniums. They’re great for potpourri.