Yes, you can still see butterflies in October, and a warm afternoon often brings them out in good numbers. The summer flowers have faded by then, so the action shifts to late-blooming asters. Their purple and white blooms pull in feeding adults long after the rest of the garden has gone quiet. A mild, sunny day can turn a fading bed into a busy feeding stop.
Fall butterfly activity surprises a lot of gardeners who think the season ends with the first cool night. It does not. Many adult butterflies stay on the wing well into fall, especially on sunny days when the air warms past 60°F (16°C). They need that warmth to fly, so you will spot more of them in the early afternoon than at dawn or dusk. On a cold, gray morning they hold still and wait. By midday, once the sun has done its work, they come back to the flowers.
The reason October matters so much comes down to food. Most summer nectar sources have finished by now, and the buffet shrinks fast. Late-season blooms become the main fuel for any butterfly still feeding or building reserves before winter. This is why a yard with good fall nectar can hold butterflies for weeks after a bare yard has none. The few plants still flowering get all the attention. Timing your blooms for the back end of the season makes a real difference, and it costs you nothing extra to plan for it.
Asters carry a heavy load here, and the research backs it up. These plants support around 100 species of butterflies and moths, both as a nectar stop and as a host plant for caterpillars. A host plant is where a butterfly lays eggs and where the caterpillars feed once they hatch. Asters also bloom late, right when other options run dry. That combination makes late blooming asters one of the best plants you can grow for October feeders. A single healthy clump can host steady traffic on any mild day, and it comes back on its own each year once it settles in.
Goldenrod plays a similar role and pairs well with asters in the same bed. Both bloom into fall, and both draw a steady stream of feeders. The gold and purple together also look great in a fall border. Goldenrod gets blamed for hay fever, but that is a myth. Its pollen is heavy and sticky, so it does not float on the wind the way ragweed pollen does. Ragweed blooms at the same time and takes the real blame. You can plant goldenrod near a patio without trouble, and the butterflies will thank you for it.
To keep your yard busy this time of year, hold off on cutting back your late bloomers too early. Let your asters and goldenrod flower for as long as the weather lets them. Skip the deadheading once October arrives. Leave a sunny spot open where butterflies can rest and warm up between feeds. A few flat stones in full sun work well for this, since the rock holds heat. Plant in clumps rather than single stems too. A larger patch of color is far easier for a passing butterfly to find than one lonely flower.
Plan for next year by adding more late-season nectar plants now, while you can still see the gaps in your fall garden. Mix early, mid, and late bloomers so something is always in flower from spring through the first hard frost. Cut back on pesticides too, since these chemicals harm the same insects you want to bring in. Do all that and you will keep seeing butterflies in October. They will drift through your asters on the warm days, long after your neighbors have packed it in for the year.
Read the full article: Butterfly Host Plants: A Complete Guide
