14 Irresistible Nantucket Milkweeds (Asclepias spp.) to Grow for Butterflies

Clasping Milkweed likes places that are sunny, with a sandy and/or gravelly substrate. These condistions exist in a number of places on the island. The distinct, broad leaves, of clasping milkweed which clasp the stem give it a rather bold architectural presence.

For companion plants, we should look to species that appreciate similar xeric conditions and won’t crowd its unique form. Consider interplanting with Little Bluestem (Schizachyrium scoparium), a superb native grass that offers textural contrast and thrives in lean soils. Another excellent partner could be Wild Indigo (Baptisia tinctoria), which blooms a bit earlier, providing nectar before A. amplexicaulis hits its stride in late spring or early summer, and its deep taproot is well-suited to sandy soils. For lower-growing companions, perhaps Bearberry (Arctostaphylos uva-ursi), a native groundcover that offers evergreen interest and spring flowers for early pollinators, would be suitable, provided the soil pH is acidic enough. The key here is to ensure good air circulation and avoid overly rich soils.

Poke milkweed presents a slightly different challenge and opportunity as compared to other milkweeds. Unlike its sun-loving cousins, Asclepias exaltata typically prefers the dappled light and richer, moister soils of woodland edges or clearings. So, if you have such a spot on your Nantucket property, perhaps with a bit more loam or humus, it could thrive. Its tall stature and drooping umbels of greenish-white to pale pink flowers are quite distinct.

Suitable companion plants would be those that share this affinity for partial shade and mesic conditions. Think about plants like Woodland Aster (Eurybia divaricata or similar native asters like Symphyotrichum cordifolium), which provide late-season nectar. Foamflower (Tiarella cordifolia) could form a lovely groundcover at its feet, appreciating similar moisture levels. For a bit of textural contrast, consider native ferns like Christmas Fern (Polystichum acrostichoides) or Marginal Wood Fern (Dryopteris marginalis) that won’t compete too aggressively for resources. Are we considering how the light conditions transition throughout the day in the proposed planting area?

Swamp milkweed, as its name would suggest, is a lover of moisture! Whether it’s a sunny streamside, a moist meadow, or a rain garden, Asclepias incarnata is in its element. On Nantucket Island, if you have areas with consistently damp soil – perhaps not a bog, but certainly not the dry dunes – this is your star. Its vibrant pink to mauve flowers are a magnet for a wide array of pollinators.

So, what companions appreciate similar conditions? Joe Pye Weed (Eutrochium maculatum or Eutrochium dubium, the latter being more coastal plain appropriate) is a classic partner, offering late-summer blooms and similar height. Cardinal Flower (Lobelia cardinalis) would provide a stunning color contrast with its brilliant red flowers, also thriving in moist soils and attracting hummingbirds. For plants that offer a different structure, consider Blue Flag Iris (Iris versicolor) or perhaps some of the moisture-loving sedges like Carex lurida or Carex crinita. Whatever plants are selected, make sure you select an area that is consistently moist.

Few-flower milkweed (Asclepias lanceolata), is often found in coastal plain habitats, savannas, and the edges of marshes. It certainly has potential for a Nantucket garden, particularly if you can offer it a spot with moist to wet, sandy, acidic soils and plenty of sun. Its slender form and striking reddish-orange flowers are quite captivating.

Given its preference for somewhat open, sunny, and moist conditions, consider pairing it with other coastal plain natives. Perhaps something like Rose Mallow (Hibiscus moscheutos), which also appreciates sunny, moist sites and provides large, showy flowers. Grasses like Switchgrass (Panicum virgatum), especially cultivars that maintain a manageable size, can provide a beautiful backdrop and thrive in similar hydrology. For a lower-growing companion, Golden Alexanders (Zizia aurea) could be suitable in sunnier, moist spots, offering early nectar. We must ensure it’s not outcompeted by more robust growers, given its “few-flowered” nature and somewhat delicate nature.

Long-leaf milkweed (Asclepias longifolia) is a bit of a specialist, often found in seasonally wet pine flatwoods, savannas, and seepage slopes, primarily in the southeastern US. Its presence in a Nantucket garden would be ambitious and would require careful site selection—namely, consistently moist, sandy, acidic soil, likely in full sun. You have to ask is such a specific habitat achievable and sustainable in your Nantucket landscape? If so, its companions would need to tolerate these specific conditions. Consider plants like the various Pitcher Plants (Sarracenia species) if you are creating a true boggy area, or perhaps Sundews (Drosera species). More broadly, for moist, acidic, sandy sites, you might look at some of the native orchids if conditions are just right, or perhaps the grass-like Beak Rushes (Rhynchospora species). This is a plant that really demands we think critically about its ecological niche.

Purple milkweed (Asclepias purpurascens), with its rich, deep magenta flowers, is a truly stunning plant. It generally prefers sites with full sun to light shade and well-drained to medium-moist soils, often found in prairies, open woods, and glades. It can be a bit more particular than some other milkweeds. On Nantucket Island, a spot with good drainage but some moisture retention would be key.

For companions, you might consider plants like Wild Bergamot (Monarda fistulosa), which attracts a plethora of pollinators and shares similar light and soil preferences. Tall Coreopsis (Coreopsis tripteris) could offer a nice vertical element and late-summer blooms. If the soil is on the leaner side, Butterfly Weed (Asclepias tuberosa), which we’ll discuss later, could be a good neighbor, ensuring a succession of milkweed blooms. When planting this milkweed be sure your intended site offers a balance between sufficient moisture and good drainage that A. purpurascens appreciates.

This charming, smaller milkweed, four-leaf milkweed (Asclepias quadrifolia), is typically a denizen of dry to mesic upland woods, rocky slopes, and clearings, often in part shade. Its delicate pinkish-white flowers appear relatively early for a milkweed. So, on Nantucket, we’d be looking for a location that mimics these conditions – perhaps the edge of a maritime forest or a partly shaded, well-drained slope. What would thrive alongside it? Consider Wild Columbine (Aquilegia canadensis), which shares a love for well-drained soils and partial shade, and its early blooms coincide nicely. Woodland Phlox (Phlox divaricata) could provide a carpet of spring color. For ferns, perhaps Marginal Wood Fern (Dryopteris marginalis) again, or Hay-scented Fern (Dennstaedtia punctilobula) if you have the space, though the latter can be a vigorous spreader. The goal is to create a gentle, woodland-edge habitat.

Asclepias rubra, or Red Milkweed, is an interesting milkweed. It typically inhabits bogs, pocosin edges, and moist pine savannas, primarily in the coastal plain of the southeastern U.S. Like A. longifolia, this species would require a dedicated spot on Nantucket with consistently moist to wet, acidic, sandy or peaty soil, and full to partial sun. Are you cultivating such specific conditions? If so, its companions would be other acid-loving, moisture-tolerant plants. Think about Large Cranberry (Vaccinium macrocarpon) as a native groundcover, or perhaps various sedges like Carex stricta. Sweet Pepperbush (Clethra alnifolia) could be a larger shrubby companion that thrives in similar wet, acidic sites and offers fragrant late-summer blooms highly attractive to pollinators. This species truly tests our commitment to replicating specific habitat niches, similar to long-leaf milkweed.

Asclepias speciosa, or Showy Milkweed, is a magnificent plant that often a feature in butterfly gardens in the US. From an ecological perspective, it’s primarily a species of the western and central United States, thriving in prairies and open areas. On Nantucket Island it is best considered a plant for container gardens due to it being far from its native range.

When people think of milkweed, it is often the ubiquitous and invaluable Common Milkweed! Common milkweed is a powerhouse for pollinators and a critical host plant for Monarchs. It’s adaptable, thriving in full sun and a range of soil types, from sandy loams to clay, though it does prefer well-drained conditions. It can be quite vigorous, so we must ask: are we prepared for its potential to spread?

For companions on Nantucket, think of other resilient, sun-loving perennials. Black-Eyed Susan (Rudbeckia hirta) is a classic choice, offering a different flower form and overlapping bloom time. Various goldenrods (Solidago species like Solidago sempervirens – Seaside Goldenrod, which is salt-tolerant, or Solidago nemoralis – Gray Goldenrod for drier spots) would provide crucial late-season nectar. For a grassy element, Indiangrass (Sorghastrum nutans) could stand tall alongside it, if space permits. The key is to plant it where its spreading nature is an asset or where it can be managed such as large field.

Butterfly Weed (Asclepias tuberosa) is a truly spectacular plant with its brilliant orange (sometimes yellow) flowers, and it’s a fantastic choice for Nantucket’s sun-baked, sandy, and well-drained soils. It’s quite drought-tolerant once established. What companions would suit this sun-lover? Consider pairing it with Lance-leaved Coreopsis (Coreopsis lanceolata) for a cheerful yellow-orange combination. Pearly Everlasting (Anaphalis margaritacea) offers silvery foliage and white flowers, creating a nice contrast and also serving as a host plant for the American Lady butterfly. For a low-growing companion, Wild Thyme (Thymus serpyllum, though not native, it’s well-behaved and a pollinator magnet) or perhaps native Prickly Pear cactus (Opuntia humifusa), if you’re embracing truly xeric conditions, could work. Ensuring excellent drainage is paramount for A. tuberosa.

Asclepias variegata, sometimes known as White Milkweed or Variegated Milkweed, is quite handsome with its white flowers and is often tinged with purplish rings. This milkweed typically prefers dry to mesic soils in open woods, woodland borders, or clearings, often in part shade but can tolerate more sun if moisture is adequate. On Nantucket, a spot with well-drained soil and some protection from the most intense afternoon sun might be ideal. Good companions could include Bluestem Goldenrod (Solidago caesia), which also appreciates dappled light and blooms in the fall. For a spring bloomer in such a setting, consider Wild Geranium (Geranium maculatum). If the soil is on the acidic side, Lowbush Blueberry (Vaccinium angustifolium) could be a productive and ecologically valuable partner. Generally, you want to aim for a woodland edge habitat.

Whorled Milkweed (Asclepias verticillata) is a delightful, fine-textured plant that thrives in full sun and dry to medium, well-drained soils, often in prairies, glades, and open disturbed areas. Its slender profile and greenish-white flowers are attractive to a wide range of smaller pollinators. Given its preference for leaner conditions, it would pair wonderfully with some of the smaller native grasses like Poverty Oat Grass (Danthonia spicata) or Purple Lovegrass (Eragrostis spectabilis), which adds late-season color. Aromatic Aster (Symphyotrichum oblongifolium) could provide late-season nectar and thrives in similar sunny, drier spots. For a very low companion, perhaps Field Pussytoes (Antennaria neglecta). The fine texture of A. verticillata provides a wonderful contrast to broader-leaved plants.

Also known as Green milkweed, Asclepias viridiflora is typically found in prairies, glades, and open woodlands, preferring full sun and dry to mesic, often calcareous soils, though it can tolerate sandy and gravelly sites as well. Its greenish, uniquely shaped flowers are quite intriguing. On Nantucket, finding a spot with full sun and excellent drainage would be crucial.

Good companions would be those that don’t mind these drier, leaner conditions. Consider Hoary Vervain (Verbena stricta), a tough plant with upright purple flower spikes. Spotted Bee Balm (Monarda punctata) is another excellent choice for sandy soils, attracting a fascinating array of wasps and bees. Little Bluestem (Schizachyrium scoparium) would again be an appropriate grass, reinforcing that prairie-like feel. The subtlety of its green flowers lends itself to being planted in places it where it can be appreciated up close.