At Hortus Arboretum, Fall is for Purple

Happy Monday GPODers!

Today we have another informative post from Allyson Levy at Hortus Arboretum and Botanical Garden. If you’ve missed them, check out her first two posts: Growing Pawpaws at Hortus Arboretum and Botanical Garden and Special Fall Plants at Hortus Arboretum.

Allyson and her partner Scott Serrano are co-founders and executive directors of a 21-acre arboretum and botanical garden in Stone Ridge, New York that puts an emphasis on native, historic, and unusual plants. If you haven’t dove into their garden’s story yet, you should absolutely check out their website. But Allyson includes so much incredible information, so I’ll let her get right to it:

When Autumn hits October in the Hudson Valley one thinks of all the yellows, golds, oranges, umbers, reds, and even pinks that imbue the foliage. Every year it’s a bit different but I can count on the red maples (Acer rubrum, Zones 3–9) offering up a fiery version of red on their leaves, while the bottlebrush buckeyes (Aesculus parviflora, Zones 5–9) leaves swoon with a butter yellow color that is both soft and sharp in hue. But purple?

Admittedly, none of the leaves on any of the trees at the arboretum are giving me a big purple vibe. The closest I may get is the Chinese dogwood (Cornus kousa, Zones 5–8), which generally has leaves turning an array of rich assortments of burgundy , crimson and scarlet reds. However, purple is abundant right now in my fall garden due to all the plants with either flowers or berries that sport all sorts of variants of the color. The richness of the varieties of purple is simply breathtaking and completely unexpected, except that this happens every October, and somehow, I forget each year!

Aconitum spp. also known as monkshood or helmetflower because both the sepals and petals of the flowers (which are similarly colored), develop into a helmet-like structure that is said to resemble the hood worn by medieval monks. It is one of those perennials that, even if it didn’t flower, produce beautiful sharply lobed leaves on a stem that can reach a height of 18 inches to two feet, making a statement in their own right. But in early October, as the flower stalk extends towards the sky and the buds begin to uncurl, this majestic plant makes a presence that cannot be unseen. I have often wanted to bring in the flower stalks for an indoor floral arrangement but remember that monkshood is in the buttercup family and like many of its close relatives, all parts of the plant are poisonous (as so many beautiful plants are). Monkshood has been used by indigenous people, to poison-tip their arrows for hunting, especially wolves, hence another common name for this plant is wolfsbane. It is also used in Chinese herbal medicine and not that long ago the leaves and roots of aconitum, specifically A. napellus (Zones 3–7) were once prescribed as a cardiac and respiratory sedative.

But don’t let this deter you! Although toxic to cats and dogs as many garden plants are, (they generally do not eat this plant) this should not be your reasoning for not growing it in your garden. Best grown in moist, organically rich, well-drained soils in full sun to part shade, I find the ones I grow to do extremely well in a part shade to dappled sun aspect and spread nicely, but not out of control.

The common name of monkshood or helmet flower has flower parts that can resemble a helmet-like structure resembling the hoods worn by medieval monks.

These stately flowers demand attention in the fall garden and look great against an autumnal backdrop.

These stately flowers demand attention in the fall garden and look great against an autumnal backdrop.

Beautyberry (Callicarpa spp.) is another October stunner which is loaded with the color purple in the form of its fruits. Whether you’re able to grow the native American beautyberry (C. americana, Zones 6–10) or one of the many cultivars of Japanese beautyberry (C. dichotoma, Zones 5–8), it is the moment when the berries begin color, so imperceptible at first that one day, they just begin, and the color is stunning. Because of climate change, my zone 6b gardens can now grow our native species of beautyberry, and a bonus for growing it is that it produces edible berries that can be made into a beautiful purple jelly. American beautyberry has berries that form around the stems making its distinct from its relatives who’s berries tend to dangle from short pedicles. My all-time favorite Japanese beautyberry is called ‘Issai’ (C. dichotoma ‘Issai’, Zones 5–8). Issai’s berries cascade down its branches making it so eye-catching. Unfortunately, this cultivar is seldom offered in the nursery trade anymore, and I think is the one worth growing over the more widely available ‘Early Amethyst’ (C. dichotoma ‘Early Amethyst’, Zones 5–8), so seek it out next spring. I say this because its branches splay downwards showing off their fruits, which gain color slowly from the tips of the branches’ the berries beginning as a light lavender or even white while the berries closest to the inner branch have become a rich purple. Although the berries are edible to humans they are not tasty, and if you are fortunate the berries can persist for several months offering up ornamental value even after the leaves have fallen, unless the migrating or wintering birds find them, another wonderful asset to this plant. I have found cutting off a few branches of the berries a wonderful decorative addition to wreath making or added to a fall floral arrangement. Slightly bruising the ends of the branches helps extend their vitality in a vase.

Beautyberry ‘Issai’ has a stunning berry display against the chartreuse hue of its autumnal leaf color.

‘Issai’ berries have various colors of berries along their stems.

American beautyberry has edible berries that grow closely along the shrub’s stem, which is the main way to identify the difference from its close Japanese relative.

Another great perennial displaying different purples during October are certain Sages (Salvia spp.). At the arboretum, we have a bed dedicated to many species and cultivars of salvias, and it is during October when they are looking their best. Mexican bush sage (Salvia leucantha, Zones 9–11) and Friendship sage (S. x ‘Amistad’, Zones 8–10) are shining now. Both are easy-to-grow salvias and readily available in nurseries. Friendship sage is a cultivar from the S. guaranitica (Zones 8–10) species also known as anise-scented sage and over the years, many crosses have been available including ‘Black and Blue’ and ‘Purple Splendor’. Friendship Sage begins blooming in the summer with its royal purple to violet tubular flowers with lips that have dark bracts at the base, and with some deadheading will continue to set forth blooms until frost. Another favorite is Mexican bush sage with wands of inflorescences that arch over the plant branches with soft, fuzzy purple sepals set off by small white flowers. Although neither of these Salvias are hardy in the Hudson Valley we feel that they are worth growing. When the threat of a hard frost is imminent, we will bring the plants indoors to enjoy the blooms for another several weeks. An easy cheat to do this is to plant your non-hardy annuals in a plastic pot that you sink in the ground during the growing season. Then by lifting the pot and bringing it indoors (make sure to check for insects) you can store it in an unheated room that does not go below freezing after the Salvia is done flowering. Then in the following year, you can plant out your “tender perennial”.

Friendship sage produces purplish flowers that bloom from summer through fall and is a hummingbird favorite.

The tender Mexican bush sage produces long wands of purple flowers and can be cut for indoor flower arrangements that last a long time.

When happy Mexican sage can grow into a large ‘shrub’-like form.

Dead man’s fingers’ (Decaisnea fargesii, Zones 6–9) is one tree we have been growing for years, and although its fruits are bluer than purple, it is so appropriate for the end of October that I can’t help but add this weird fruiting plant to the list. This small growing, multi-limbed tree or large shrub is also called “blue bean tree” or “blue sausage fruit”. It produces eye-catching cylindrical-shaped fruits that are edible. One may say they are more of a novelty fruit since they are full of tiny seeds that, although edible, are a bit annoying to eat. It is the arils (the pulpy part around the seeds) that are yummy and taste a bit like watermelon. This plant from Western China, Nepal, and parts of India is a very uncommon garden plant in the U.S. In spring, the plant produces gorgeous bell-shaped yellow & purplish-blue flowers that dangle from the branches and are uniquely beautiful. This zone 6 plant likes a full sun place in the garden and is a great specimen tree for those looking for the unusual.

A cluster of dead man’s fruits resembles a ghoulish sight for Halloween.

An open “finger” of the fruit of Decaisnea fargesii shows the watermelon-like pulp surrounding the seeds.

Thanks again, Allyson, for an enlightening and informative post on some incredible plants. I’m absolutely obsessed with dead man’s fingers’!

Do you grow any purple plants in fall? How about any other colors outside the expected reds, oranges, and yellow? Let us know in the comments, or follow the directions below to share photos of your fall garden.

 

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