Gardening for Butterflies

  • Variable checkerspot butterflies need nectar for food while they search for the appropriate host plant to lay their eggs on. Photo: Marc Kummel
  • Butterflies will often deposit their eggs on the underside of a leaf where they are more protected. Photo: Marc Kummel
  • Caterpillars will consume several plants but their principal host plant is sticky monkeyflower. Photo: Marc Kummel
  • An adult butterfly will emerge from the chrysalis formed by the caterpillar. Photo: Marc Kummel

The lovely winged jewels we call butterflies are the pioneering and reproductive life stage of an insect that goes through 3 other distinct stages: eggs, larvae (caterpillars), and pupae (chrysalids). The adult stage, the butterfly, is technically called the imago. About eighty percent of all insects are holometabolus, which is a way of partitioning resources, so that each life stage does not compete with any other. Your habitat garden needs to provide for the needs of every life stage in order for there to be butterflies.

The purpose of a butterfly’s often short life “on the wing” is simply to find a mate and the host plant on which to lay the eggs of the next generation. They will be looking for the plant that their hatched larvae will eat; many butterfly species are extremely choosy about what plant that is. The adult butterfly will need nectar for energy as she hunts for her special host plant. If you are interested in attracting a specific type of butterfly, check the handout at right, Butterfly Larval Host Plants, to learn some of the appropriate plants.

To get a good indication of which butterfly species are already present in the general area of your garden, start with specimens of flowering plants that are noted as really good nectar sources, and then observe the butterflies that come into your garden to feed. Buddleias, verbenas, and lantana, though not native, bloom for a long period of time and are loved by butterflies. Flowers in the composite family (aster, sunflower, or daisy), offer a landing pad when fully opened, which is important for the larger butterflies like the Monarchs. Flowers in the composite family are composed of hundreds of individual disc flowers, and petal flowers, and each of these tiny flowers provides nectar and pollen, thus providing a lot of food energy in one place!  If you can, allow “managed” populations of weeds such as Italian thistle, English plantain, and cudweeds, which are favored larval host plants of some beautiful butterfly species.

Butterflies are not important pollinators of plants, but their beauty certainly adds to the charm of any garden!

Thinking About Weeds and Wildflowers

Micro-Habitats; Knowing Your Land

My husband and I live on a south facing hillside situated above the Novato Creek floodplains; it’s a beautiful, warm, and sunny spot with a great vantage point. Our hill, called Cherry Hill on some maps, is a part of one of the ridges extending from Mt. Burdell, the 3rd highest peak in Marin County, and we’re directly facing Big Rock Ridge, the 2nd highest spot in Marin. When the skies are clear, we can actually see just a little tip of Mt. Tamalpais, the highest peak in Marin! To the east, we can see the twin peaks of Mt. Diablo, which is the highest peak of all in our area and therefore the base meridian of much of northern California.

The views are wonderful here on our land, but the rainfall is sometimes disappointing; while other places in Marin are measuring and inch or so, we might get ¼ of an inch of rain! We’re in a rain shadow; I can see all the rain falling on the north side of Big Rock Ridge and in Indian Valley, but the clouds are often blown east. If they do get to our side, there’s not much moisture left. 

Even so, with not much more than an inch of rain, I’m witnessing an almost instantaneous re-greening of the landscape! Within days thousands of seeds are germinating; lots of grasses, and a great variety of weeds and wildflowers. This is where the fun begins. I love the challenge of identifying these minute plantlets. Sometimes I’m already so familiar with the plant that I know it from the cotyledons, but very often I need to see the first true leaves before I really know what they are.

Thinking About Weeds

Annual grass seeds are amongst the first to germinate, and of course wild oats (Avena species) are well represented. Wild oats, very different looking than the native Oatgrass (Danthonia californica) were introduced from Europe and brought to California, most likely with the very first Spanish settlers who brought livestock, and with them the seeds of these grasses. In Europe, during the olden times, the leafy new spring growth of one wild oat species (Avena sativa) was used as a medicinal to treat various conditions, including diminished sex drive. This is where the term "sowing one’s wild oats" originates from!

Along with the annual grasses come lots of thistle seedlings; their cotyledons are large and somewhat spoon-shaped. I can identify Italian thistles (Carduus pycnocephalus) easily when the first set of small and somewhat spiky, medium-green true leaves have developed. Some of the non-native weeds, including thistles, that plague wild areas in Marin, are thought to have been brought to the county by Samuel P. Taylor in raw materials for his paper mill. At first there was plenty of wood pulp locally available, but as those sources dwindled, and while the demand for paper kept going up, he also made paper using rags that were imported from Europe. It’s within these supplies that the seeds of some European weeds are thought to have "hitched a ride".

Here’s where my thoughts about weeds differ from those of many others; weeds are not all bad!