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Look Out for Black Swallowtail Larvae in the Fall Herb Garden

Look Out for Black Swallowtail Larvae in the Fall Herb Garden

Second instar, Black Swallowtail larva. Image Credit Matthew orwat

Second instar, Black Swallowtail larva. Image Credit Matthew orwat

 

Busily devouring dill and fennel, the lime green, black striped caterpillars in the UF IFAS Extension Washington County Office have quickly become a popular attraction.  It is fortunate that the South’s climate is warm enough to allow for three generations of this species every year.

 

Larvae Busily Devouring Dill. Image Credit Matthew Orwat

Larvae Busily Devouring Dill. Image Credit Matthew Orwat

 Soon, the caterpillars of the Black Swallowtail (Papilio polyxenes asterius ) butterfly species will continue their pupae stage by forming a chrysalis and emerging as one of Florida’s most recognized swallowtail butterflies. 

The chrysalis is formed by two glands located inside the caterpillar that secrete silk.  The silk threads stick together and harden when exposed to fresh air.  The hard, protective coating is usually camouflaged from predators and blends in with the environment.  Inside the chrysalis, the process of metamorphosis continues as the adult structure forms while the juvenile structure breaks down.  The insects are very inactive during this time as they grow and change.  This stage can last from two weeks to an entire season in temperate climates and tropical dry seasons.  When hormones indicate it’s ready, the butterfly emerges by splitting the chrysalis open either biting its way out or using spit to soften the ends.

 

 

Green Chrysalis. Image Credit Don Hall UF IFAS

Green Chrysalis. Image Credit Don Hall UF IFAS

The Black swallowtail has quite a heavy appetite for such a small creature.  They eat a variety of plants in the carrot family (Apiaceae) such as dill, fennel,  parsley, celery, and carrot leaf. In addition to these cultivated species, they will feast on mock bishopweed, roughfruit scaleseed, spotted water hemlock, water cowbane, and wedgeleaf eryngo. They have also been known to enjoy Common Rue (Ruta graveolens L.).

They exhibit several interesting behaviors throughout their life cycle. For example, when they feel threatened the Black Swallowtail larvae will exhibit yellow antennae-like structures called osmeterium. These flare out and emit a foul odor, like rotten cheese, if one’s finger gets too close.

Osmeterium on display. Image Cretid Matthew Orwat

Osmeterium on display. Image Credit Matthew Orwat

 

Even though they are voracious plant eaters and honorable defenders of their territory, butterflies play a vital role in agriculture by pollinating crops and flowers.  They’re an indicator of a healthy ecosystem; an abundance and diversity of butterfly species illustrate the overall health of an area.  With their acute sensitivity to contaminants and toxins, butterfly populations will not be found in polluted areas.  Recognized for their beauty, butterfly watching has also become a popular hobby and pastime. 

Photo courtesy of Donald Hall, University of Florida.

Photo courtesy of Donald Hall, University of Florida.

It’s never too early to think about planning a butterfly garden.  For more information on creating a backyard butterfly habitat, download this 4-H fact sheet for kids and parents.   For more information on this specific butterfly, visit the UF IFAS EDIS website for a publication on the Eastern Black Swallwtail.

Additional Content by:

Julie Pigott Dillard, Director, UF IFAS Extension Washington County

Giant Swallowtails and Satsumas

Giant Swallowtails and Satsumas

Gardeners that have Satsumas, commonly known as orange mandarin (Citrus reticulate), probably have experienced a caterpillar called Orangedog.  It is a chewing insect that feeds on citrus foliage including Satsuma and a few other plant species.  The caterpillar is dark brown with creamy-white, mottled markings and is the larval stage of the giant swallowtail (Papilio cresphontes). It is a striking, wonderfully “exotic”-looking butterfly that is very abundant in Florida. 

Young larva of the giant swallowtail, Papilio cresphontes Cramer, (illustrating bird dropping mimicry) Credit: Donald Hall, University of Florida

Young larva of the giant swallowtail,  Illustrating bird dropping mimicry.
Credit:
Donald Hall, University of Florida

Many who have encountered the caterpillar for the first time describe them as looking similar to bird droppings.  They can grow up to 1.5 to 2 inches in length and are the larval stage of the adult giant swallowtail butterfly.  Established Satsuma trees can easily withstand the loss of a few leaves by Orangedog feeding.  Small or newly planted Satsumas can be infested with numerous Orangedog Caterpillars on occasion, especially a single tree growing in a landscape.

A simple control measure consists of finding and crushing eggs and larva (GH-026). Bt, a biological control for most caterpillar species, is effective but should rarely be used since the beauty of this butterfly far outweighs the damage caused by them.

 Adult giant swallowtail, with wings closed. Credit: Donald Hall, University of Florida


Adult giant swallowtail, with wings closed.
Credit:
Donald Hall, University of Florida

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Edible Blossoms For You!

Add the easy-to-grow garden nasturtium to your vegetable or flower garden!

Dress up a ho-hum salad with a vibrant blossom or two just like some of the high-end restaurants. The first taste you experience will be sweetness and then a pleasant peppery flavor emerges. Not only can you eat the flowers but the leaves can also be tossed into your salad and the immature seed pods can be pickled and eaten similar to capers.

Brightly colored garden Nasturtium

Photo courtesy of the Mendocino Coast Botanical Garden

Garden nasturtium, known to botanists as Tropaeolum majus, is an annual that originated in the Andes of South America.  Seed and plants are commonly found in garden centers, although a greater variety is available when purchased from seed catalogues or online. A variety of cultivars are available, from dwarf bushy types to climbing or trailing types. Perky blooms in vivid shades of orange, yellow, pink and red are often produced in abundance.

This annual is easy and fast to grow from seed.  If transplanting from small potted plants, make sure not to disturb the delicate root system during the transplant process. Give them partial to full sun and regular watering, even though they are drought tolerant. They prefer a lighter, sandy, well-drained soil and don’t perform as well in dense, rich soils. Be careful with the fertilizer as too much nitrogen will produce lots of green foliage but few blooms.

 

[warning]Aphids like to feast on the succulent flowers and foliage as well, so be diligent in scouting for this pest. Control is usually adequate by dislodging them with a spray of water or insecticidal soap. Insecticidal soap will cause the aphid to try out and dessicate.  Be careful to spray the undersides of the leaves as well for complete control. Make sure to apply products that are safe for food crops and follow all label instructions.[/warning]

 

In the Florida panhandle, garden nasturtium can be a part of the garden year-round. However, they generally decline and stop flowering with the onset of the full brunt of the summer heat unless a bit of afternoon shade is available. When planted late in the fall, they are susceptible to frost damage but often will recover.

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For more information from the University of Florida, please see:

Garden Nasturtium, Tropaeoleum majus L.

Gardening in a Minute: Nasturtium

Summer Bulbs

Thinking of bulbs for the garden? Summer is not necessarily the time of year that gardeners think about beautiful blooms from bulbs and bulb-like plants, but there are many that bloom in the summer garden.

In general, many types of plants with an underground storage organ are classified as a bulb.  These  include plants with tubers, rhizomes, or corms.  True bulbs including Lycoris and Crinum lily are compressed stems with a growing point surrounded by thick, fleshy scales.  Corms such as Crocosmia are solid masses of stem tissue with a terminal bud and side nodes.  The rhizome is an underground stem that grows laterally, with representatives of this type being blackberry lily and ginger.

It is likely that your garden is full of bulb-like plants and you were just not aware of their underground beginnings.  If you want to consider a few more for the summer garden, here are some good choices.

Blackberry lily is a member of the Iris family that offers good summer bloom in our northern Florida gardens.  Plants form sprays of foliage about 2 feet in height with stalks of orange flowers with red spots.  Plant in full sun or partial shade and supply with well drained, amended soil.

A hairstreak butterfly visits the Blackberry lily flower.

A hairstreak butterfly visits the Blackberry lily flower.

Blackberry lily foliage_bbolles

Another bright summertime bloomer is Croscomia.  Commonly overlooked early in the year as foliage regrows from the cold, the bright orange flowers that emerge in summer make it a feature in garden beds.  Plants grow well in both full sun and partial shade but clumps can expand easily beyond the desirable planting area.  Thin out every few seasons to keep the clump manageable.

A tuberous perennial that will have stunning flowers closer to eye level is the Gloriosa or flame lily.   Plant stems will wind around a trellis or garden feature, hold on with tendrils, and support large upward-curved petals.  Flower colors are red, yellow, orange, or mixes of several colors.   Flame lily prefers sunny locations and lots of moisture in the growing season.  Winter soils should be drier to prevent tubers from rotting.

Flame lily growing with a spring blooming vine.

Flame lily growing with a spring blooming vine.

All of these options can enhance your garden and extend your bulb growing season beyond the spring. Happy Gardening!

Gaillardia pulchella for Summer Color

Gaillardia pulchella for Summer Color

Gaillardia is a favorite one of many wildflowers throughout the United States.  It is a member of the Aster family, and is most commonly known as Indian Blanket or Blanket Flower.  Individual plants can reach up to 2 feet high.  They are heat and drought tolerant and, in Northwest Florida, flower from summer through fall.

The entrance to the Gadsden County Extension Office is flanked on either side by stands of Indian Blankets.  Blooms are an array of red, orange, and yellow.  While it may be rare to find a flower with the center cone and petals completely yellow or orange, they are evident in our garden.  What most people find peculiar is appearance of tubular, trumpet-like, florets on the flower ray.

Gaillardia pulchella

Gaillardia pulchella

The striking display of flower color Indian Blanket offers is not its only feature. It is also a source of nectar for many different butterfly species.  Stephen Brown, a horticulture agent in Lee County Florida, has an excellent publication on Gaillardia pulchella that lists this plant species’ interesting attributes.

Garden Fireworks

Garden Fireworks

Bring your own blend of fireworks to the garden this July by adding the Red Rocket Russelia, Russelia sarmentosa to a full sun area.

Russelia_bolles

Russelia sarmentosa. Image Credit Beth Bolles, University of Florida

 

A favorite perennial to those who grow it, the Red Rocket has many positive qualities that make it a must have for everyone.  Plants form a large group of arching stems that grow 5-6 feet in height.  Clusters of tubular red flower occur at each node, covering the entire stem in color.  Flowering occurs soon after regrowth from winter cold  and continues until the first frost.  Once established plants perform well with occasional irrigation or a routine rain shower.  The added bonus of this colorful perennial is that hummingbirds visit flowers often to feed on nectar.