Helianthus for Sunny Yellow Fall Flowers

While every other perennial plant is winding down at the end of the summer gardening season, the golden heads of Helianthus are approaching peak show. You will notice that I included the genus but not the species. That is because I cannot tell one species from another. What I can tell you is that I spotted this lovely fall-flowering yellow daisy last autumn in a ditch in front of a house with prominently displayed No Trespassing signs. I jumped from the car, snipped one stem of spent flowers, and zoomed down the street before the owners could lock and load.

I stripped the seeds from those dried flowers and started growing them in my laundry room. (This was before the greenhouse arrived.) I had a couple of small plants to set out in spring. They have repaid my care by throwing a dozen lovely yellow flowers per plant. These are hardy perennials for zones 6-9, so I expect the show to improve next year and every year thereafter.

Helianthus, commonly called Swamp Sunflower or Narrow-Leaf Sunflower, is a native that attracts songbirds and butterflies. It has rough, narrow leaves and thin stems that can be damaged by winds or weighted down by its numerous flowers. It is a food source for several butterfly larvae species. Plants are moderately deer resistant.

Perennial species of Helianthus, pronounced hee-lee-AN-thus, share common cultural needs. They flower best in full sun but will tolerate partial sun. They want acidic soil. Plants will get quite tall – to ten feet in fertile soil and sufficient moisture. That is too tall to fit into most garden borders. This too-tall problem can be remedied by pinching plants back several times in spring and early summer to encourage branching and reduce their height. Don’t pinch after mid-summer to avoid removing flower buds.

Allow spent flowers to remain on stems to reseed naturally and your fall garden will soon feature these happy yellow flowers, perfect for inclusion in seasonal flower arrangements.

These are two of the seedlings I started from seed. I will not deadhead them. Instead, I will allow the fallen seeds to start new plants, resulting in a fuller planting in coming years. The bumblebees LOVE these flowers.

Don't Discard Your Fall Mums

Long-flowering, colorful Mums are ideal for adding spots of bright color to the autumn garden. There are 30 different species in the Chrysanthemum genus, broadly categorized into “florist” mums and “hardy” mums. They are further broken down into different types of blooms: cactus, cushion, anemone form, incurved, intermediate, Korean, pom-pom, spider, reflex, single, others.

All Chrysanthemums demand full sun, rich soil, and regular water. Container specimens must have good drainage to prevent root rot. Plants have a shallow root system, and may need daily irrigation during the hottest part of the summer. Flowers come in a wide range of colors: yellow, orange, burgundy, purple, bi-colors. Good air circulation will prevent leaf issues. Plants are perennial in zones 5-9.

In garden beds, pinch plants back often in spring to keep them compact and get more blooms. Stop pinching in late June so they have time to develop bloom buds. Bud formation is triggered by the shorter days of late summer and early fall. Divide plants in spring, every two or three years, discarding the woody interior section and replanting the vigorous outer portions. Plants can be propagated from cuttings.

Potted (“florist”) Chrysanthemums are found at big box stores and grocery stores in the fall. These have been greenhouse bred and chemically treated to keep them short and light manipulated to make them bloom on cue. They are typically not as cold-hardy as the selections grown for borders. Gardeners in warmer zones can keep them in a freeze-free area through winter, then plant them out into the garden in spring. Some will survive and return the following year, but they won’t ever be compact like their original supermarket form. Plants may bloom much earlier (May or June) and be much taller (24-30”).

Chrysanthemums are toxic to humans, horses, dogs, and cats. Their pungent foliage makes them less likely to be browsed by deer or rabbits.

Toad Lily Heralds Autumn's Onset

When Toad Lilies start to bloom, I know that autumn is arriving. Toad Lily is a common name for either Tricyrtis hirta (“Hairy Toad Lily”) or Tricyrtis formosana (“Formosan Toad Lily”). It is difficult for me to distinguish between the two visually. Leaves of Tricyrtis hirta are noticeably hairy to the touch. The flowers resemble small orchids, with inner petals and outer sepals that look like petals. Most are white with purple freckles, about one inch across. They can be held individually, but usually occur in clusters. Upward-facing flowers form on arching stems, above alternate leaves held in a ladder-like arrangement. Plants may reach 36 inches but are usually shorter. The intricate flowers are best appreciated when viewed up close. Site them near patios or seating areas if possible.

Toad Lily likes partial to full shade and acidic-to-neutral, moist soil with plenty of organic matter. Hirta is cold hardy in zones 4-8; formosana is cold hardy in zones 6-9. In the Mary Snoddy garden, they pair well with hosta and ferns. They will spread slowly by seeds or rhizomes, and are not invasive. Tricyrtis is pronounced tri-SUR-tiss.

Bees, butterflies, and hummingbirds visit the flowers. Plants are occasionally bothered by aphids, which can spread a viral disease, or by anthracnose fungus, which causes orange spots on the leaves. Use soaker hoses rather than overhead watering to prevent anthracnose. Treat aphids with an insecticidal soap rather than a chemical insecticide to avoid harming pollinators. Rabbits like to nibble on foliage. I use Milorganite in the Snoddy garden as a deer repellant, and it seems to have kept the bunnies away also. Now if I could find something non-toxic that would repel voles…

This Toad Lily is just beginning to bloom. Note the overlapping leaves along the stem. The swollen nodes along the stem are buds, waiting to open into flowers.