Thursday, February 25, 2010

Curtiss' Milkweed - Asclepias curtissii

Curtiss' milkweed is an extremely rare endemic species, listed as endangered by the state and confined to deep excessively well-drained sandy habitats in the peninsula.   Although widespread throughout the peninsula, its populations are widely scattered and localized.  It occurs only in excessively well drained sands with lots of sunlight.  
This deciduous species eventually becomes quite long and lanky.  The thick main stems may reach 2-4 feet long, but they often lean over and this makes them seem shorter.  The leaves are deep green and oval in shape, usually with a noticeable undulating margin. 
Flowering occurs in the summer.  The few flower heads (umbels) are confined to the ends of the main stalk and consist of 20-30 individual flower buds.  These open to become clear white in color.
Although Curtiss' milkweed would make an excellent addition to a butterfly garden, given its abundant foliage and large stature, I am not aware of anyone ever propagating it.  Perhaps this will change someday given the increased interest in native plants and butterfly gardening.  Until then, we can only hope that the wild populations will be protected sufficiently to maintain this interesting and truly Florida species in our flora.

Largeflower Milkweed - Asclepias connivens

I love this milkweed despite its rather small stature and simple greenish flowers.  Largeflower milkweed (Asclepias connivens) occurs throughout Florida and much of the Southeastern Coastal Plain in open wet flatwoods and savannahs.  It seems to require these open and seasonally wet conditions to thrive and its populations are always widely scattered and localized. 
Like other members of this genus in Florida, largeflower milkweed is deciduous and dies back to the ground each winter.  When it emerges the next spring, it is difficult to notice amongst the surrounding vegetation.  The stem is rather stout, but often leans; making it shorter in stature than its actual length of 2-2.5 feet.  Along the stalk are short linear leaves, opposite each other.
Flowering occurs in the summer.  As its common name implies, largeflower milkweed produces large flower buds.  Individual blooms are almost 1 inch across, rather rounded in appearance, and light green in color.  Only a few flowers occur in any one head and only a few heads occur - near the end of the main stem.
Largeflower milkweed is unusual in appearance, but may not be "attractive" enough to ever warrant its commercial production.  I know of no one who has ever offered this species for sale and I have never been fortunate enough to stumble upon one with ripe seed to try it myself.  I suspect it is a difficult species in cultivation because in nature it is always extremely localized.  If you are fortunate enough to try it yourself, plant it in open sunny areas where the soils are moist to nearly wet during the summer rainy season, collect some seed, and drop me an e-mail...

Savannah Milkweed - Asclepias pedicellata

Savannah milkweed (Asclepias pedicellata) is yet another diminutive milkweed that largely goes unnoticed in the Florida landscape.  It occurs statewide in open upland habitats, such as pine flatwoods and prairie.  It is not especially drought tolerant, but prefers average conditions during much of the year and moist soils during the summer rainy season.
Savannah milkweed is deciduous during the winter.  It emerges in the spring, but is easy to miss as it never reaches a height much taller than about 1 foot.  Its leaves are linear and only about 1-2 inches long. They also are opposite on the stem.
Flowering occurs in the summer.  Small heads of flower buds near the top of the main stem open to become rather plain yellowish flowers.  They are quite distinctive because the petals do not curve backwards, and each is urn shaped. 
I am not aware of anyone ever offering savannah milkweed for sale commercially and it is not likely to ever generate much demand because of its size and lack of showy blooms.  It would make an interesting milkweed to a mixed wildflower planting, however.  We have not grown this species at Hawthorn Hill and do not intend to add it unless someone inquires.

Florida Milkweed - Asclepias feayi

Florida or feay's milkweed (Asclepias feayi) is a small, but rather distinctive member of this genus.  It is endemic to Florida and found only within the southern half of the state.  It is native to well-drained upland habitats; especially xeric flatwoods and sandhills with high levels of sunlight.
Florida milkweed is a perennial which dies back to the ground each winter.  It emerges in the early spring, but often goes unnoticed until it blooms in mid-summer because of its small stature and thin foliage.  At maturity, Florida milkweed rarely stands taller than about 2 feet.  Its thin leaves are several inches long and mostly opposite each other on the stem.
Blooming occurs during the summer.  Like the fewflowered milkweed (A. lanceolata), the flower heads are few and confined mostly to the top of the main stem.  Each contains less than 10 white flowers with a bit of purple near the center.  Unlike most milkweed flowers, the petals are not strongly recurved, but point outward - giving each a star-like quality.
Because of its small stature, Florida milkweed is not the first choice for butterfly gardening enthusiasts.  The caterpillars would quickly devour it; especially if there was not sufficient quantity around.  Its somewhat subdued flowers are also not likely to put it in great demand, but despite all of this, it is a very interesting species and well worth adding to a mixed wildflower planting.  Like many of Florida's upland species, it requires good drainage and plenty of sun to thrive.  Place it in small clusters near the front of the garden and mix it with other species, small in stature.
I am not aware of anyone that has ever grown this species commercially and we have not had the good fortune to find seed at the right time yet.  But, we continue to hope...  If you are interested, let us know and we will increase our effort.

Fewflower Milkweed - Asclepias lanceolata

Fewflower milkweed is a tall thin species with thread-like linear leaves and small heads of bright orange blooms.  It occurs throughout Florida in open marshes, wet prairies and savannahs, and in much of the Southeast.  For much of the year, this milkweed is inconspicuous within the surrounding foliage.  It is completely deciduous during the winter and when it emerges in the spring it consists of a very thin stem and long thin opposite leaves.  Eventually, it reaches a mature height of about 4-5 feet. 
Flowering occurs in early summer.  Atop the main stem and on a very few side branches, flower buds are formed which contain less than 10 flowers each.  These flowers may be small in number, but are a brilliant orange to nearly brick red in color. 
Fewflowered milkweed makes a very interesting addition to a mixed wildflower planting in open wet-soil conditions.  It does not thrive if soils remain dry for too long, but it will handle part sun reasonably well.  We have grown this species for several years in our wetland wildflower planting, but it is a bit touchy concerning conditions and we have not propagated it to any real extent.  If you are interested in it, please let us know and we will make a greater effort to bring it into cultivation.

Sunday, February 21, 2010

Longleaf Milkweed - Asclepias longifolia

Longleaf milkweed (Asclepias longifolia) is found throughout Florida, and much of the Southeast, in moist to wet pinelands and savannahs.  In these habitats, it receives plenty of sun and moisture.  During much of the year, this milkweed is rather inconspicuous.  As a deciduous species, it spends its winter dormant and beneath the soil surface.  In early spring, it emerges, but is never much more than a few thin basal leaves.  By late spring, each plant stands about 2 feet tall with a rigid, but thin, main stem and numerous 3-6 inch linear leaves. 
The flowers occur in round umbels; several near the top of the main stem.  They are small and whitish.  The tips of the strongly recurved petals and the tips of the corollas are often a purplish pink.  Blooming is most common in late spring, but may occur as late as early summer.  Seed production follows about 6 weeks later.
Longleaf milkweed has never been offered (to my knowledge, anyway) for sale commercially by any nursery associated with AFNN (Association of Florida Native Nurseries) and it is not likely to as it is not as showy as other native milkweeds and is rather habitat sensitive.  Despite that, this species has a charm all to itself and would warrant inclusion in a mixed wildflower savannah or wet meadow planting.  It is easy to grow from seed if you are lucky enough to time it correctly.  Longleaf milkweed is not a species I have ever grown in my home landscape, but we could search for it for propagation at Hawthoorn Hill if there was interest.

Sunday, February 7, 2010

Purple Milkweed - Asclepias humistrata

Purple milkweed (Asclepias humistrata) is native to the northern two-thirds of Florida and resident to habitats with excessively well-drained sands and full sun. It is a multi-stemmed deciduous perennial which dies back each fall and emerges in the early spring. Purple milkweed is a robust, but sprawling plant which sends its stems in all directions across the ground. At maturity, these stems may be more than two feet long. Its common name comes from the color of its large arrow-shaped leaves. They are a purplish green with pink-purple veins throughout. Purple milkweed blooms in early summer at the ends of each stem. The flowers themselves are a dull pinkish white and they occur in large rounded heads which are held about one foot off the ground. Purple milkweed is not the most beautiful of our native milkweeds, but its variegated foliage and large flower masses make it an interesting addition to a large planting area. Do not attempt it in small spaces as it will overwhelm them. This is a difficult species to maintain in containers and the landscape. It will rot quickly if planted in soils that stay too moist, but if you have excessively well-drained sands in a sunny location and a bit of space, purple milkweed provides a great many benefits to a mixed wildflower planting.

Swamp Milkweed - Asclepias perennis

Swamp milkweed (Asclepias perennis) is the “other” swamp milkweed, but quite a different species than A. incarnata, described elsewhere in this blog. As its common name implies, swamp milkweed occurs in a variety of wetland habitats, including semi-shaded forests. It can survive lower amounts of direct sunlight than our other native species, but it will become lankier and flower less abundantly. Swamp milkweed requires good soil moisture to prosper. It has some drought tolerance and is more easily grown than swamp rose milkweed, but it will eventually disappear if not provided with plenty of water during the summer months. This is a somewhat diminutive species. At mature height in the late spring, its many stems rarely stand taller than 2 feet. Each is densely covered by lance-shaped bright green leaves approximately 2 inches in length. Swamp milkweed blooms in the summer. Although it does not produce large flower heads, each is composed of bright white flowers which are attractive. This wildflower is commonly propagated for home gardeners and is quite hardy if used in locations that stay moist to wet. For best effect, plant it in small clusters of at least three and use it near the front of the planting bed.

Butterfly Milkweed - Asclepias tuberosa

Butterfly milkweed (Asclepias tuberosa) is the most widely recognized native milkweed for the home landscape. It occurs across much of North America in a wide variety of habitats, but in Florida it is confined to areas of well-drained sandy soils and it will quickly perish if not provided these types of soils. Do not attempt to grow this plant from seed or stock which originates from sources outside of Florida. It may grow for a season, but rarely persists. Florida butterfly milkweed is often a rather gangly plant. It rarely becomes the fuller more floriferous specimens seen in other states. Often a single-stemmed individual with multiple branches, it emerges in early spring and eventually reaches a mature height of 12-24 inches. The leaves are oval and a rather dull green in color. What makes it so spectacular are its blooms. Butterfly milkweed may bloom at any time from late spring to late fall and individual plants will produce flowers successively throughout this time period. Large rounded umbels of bright orange to brick red or nearly yellow flowers provide a color accent few others can produce. Plant it in small clusters for the most impact and near the middle portion of a mixed wildflower planting. Butterfly milkweed is extremely touchy in regards to growing conditions. If you can provide the very well-drained sands it needs, use it in numbers.  Many commercial nurseries in Florida list it in their catalogs, but it is in such demand that few actually have it available at any one time.  Be prepared to look around a bit before actually obtaining your plants, but the wait will be well worth it.  Once you have some, sow your seeds in good potting soil just below the soil surface and make more.

Swamp Rose Milkweed - Asclepias incarnata

Swamp rose milkweed (A. incarnata) is one of the most beautiful members of this genus and well worth making a place for in the home landscape. Native throughout peninsular Florida, it occurs in moist to wet soil habitats in sunny locations. In the home landscape, it needs similar conditions to thrive, but it can tolerate occasional short-lived drought once established. Swamp rose milkweed emerges in the early spring and eventually reaches a mature height of about 3-4 feet. The stems are stout and multi-branched while the leaves are lance-shaped, up to 6 inches long, and abundant along the stems. Blooming occurs in summer. Large rounded heads (umbels) of rose-pink, slightly fragrant flowers adorn the ends of each stem and are quite showy. Use this species in small clusters of 3-5 each for the best effect and plant it in locations that stay wet in the summer months; the edges of ponds and other water features. In our Pinellas County landscape, we created a wetland where this species has prospered.  Recently, I have discovered the trick to germinating the seed - it needs to be cold stratified.  As a result of that, we are now able to offer this beautiful wildflower for sale.  Swamp rose milkweed is a favorite larval food plant of the milkweed butterflies - monarchs, queens, and soldiers - and it is one of the best milkweeds for nectaring butterflies of all kinds. If you decide to use it, however, keep it wet to moist during the heat of summer or you are likely to lose it.