Originally published in The Forest Farmers Handbook: A Beginners Guide to Growing and Marketing At-Risk Forest Herbs by United Plant Savers & Rural Action (available here).
There are two species of ramps (Allium tricoccum and Allium burdickii) commonly found in the forests of eastern North America. These species are similar in physical appearance and flavor profile and will be simply referred to as “ramps” throughout this publication. Ramps are one of the first forest herbs to emerge in the spring and are highly sought after for their pungent garlic-like flavor. Ramps typically emerge several weeks before the leaves fully develop in the forest canopy and take advantage of the high amounts of sunlight that reach the forest floor. With plenty of early spring sun, plants grow rapidly from April to May and build up energy reserves in the bulb to fuel growth later in the season. Leaves and bulbs can be harvested from March to May depending on geographical location (Chamberlain et al., 2014), with plants reaching peak flavor and tenderness by mid to late April.
Historically, ramp populations were relatively abundant and were utilized as both food and medicine by indigenous North Americans and early European migrants. Many European settlers were already familiar with ramps when they came to North America, which were very similar to the “ramsons” (Allium ursinum), a Eurasian relative of Allium tricoccum (Edgar et al., 2012). As one of the first edible greens to emerge in spring, ramps were seen as a source of fresh vitamins and minerals after a limited winter diet, and the leaves were consumed as a spring tonic and blood purifier (Cavender, 2006). The leaves and bulbs were also used as an emetic, laxative, cold remedy (Small, 2013) and de-wormer (Cavender, 2006).
Ramp populations are not as abundant as they once were, largely due to overharvesting and the loss of suitable forest habitats (Ritchey and Schumann, 2005). While the rise in popularity of ramp festivals in the Appalachian region has put pressure on wild populations, the increased demand for ramps in high-end restaurants and in large metropolitan markets, such as New York City, Chicago, Seattle, and Washington, D.C., has also contributed to increased harvest pressure on wild populations (Schreibstein, 2013).
Ramp bulbs begin to elongate and unfurl their first leaves in early March as soil temperatures reach approximately 45°F – 50°F. By taking advantage of available sunlight, plants grow rapidly and reach at least 2-3 inches of growth by the beginning of April (Facemire, 2009). By mid-April, both the leaves and bulbs will have increased significantly in size and are considered to have peak flavor and tenderness at this stage of development. Plants are considered fully mature by mid to late May, and the leaves begin to discolor and turn yellow as plants begin to shift to the reproductive stages of development. By the time the flower stalk begins to emerge from the bulb in July, the leaves have completely disintegrated and are no longer visible (Nantel et al., 1996).
The white umbel of flowers borne on the flower stalk begins to bloom by late July (Nault and Gagnon, 1988), and the seeds will continue to develop through August, before fully ripening in September. Mature seeds, which resemble shiny black BB’s, are fully formed and ready to harvest by mid-September. Seeds will persist on the stalk for several weeks to months until they naturally fall from the plant or are shaken loose by wind, rain, or snow. Ramp seeds exhibit a complex “double-dormancy” and require an 18-month period of stratification before they will germinate. Stratification is a process where seeds are exposed to the natural fluctuations of seasonal temperatures, which provide environmental cues that break seed dormancy and stimulate germination. Typically, with this type of dormancy, warming temperatures during the spring and summer months break root dormancy, and cold temperatures during the following fall and winter months break shoot dormancy (Davis and Greenfield 2001).
As winter approaches, ramp bulbs enter a period of dormancy where active growth ceases until the following spring. During the winter months bulbs actually decrease in size and weight by shedding the outer-most layers of the bulb that were formed during the previous growing season. By mid-February the outer layers have been completely shed, and the plants are ready to start the growth cycle over again (Facemire, 2009).
Ramps have a long pre-reproductive period and do not typically become reproductively mature until after six or seven years of growth. Ramps are capable of both sexual (seed) and asexual (clonal) modes of reproduction, but evidence suggests that as populations increase in size and density, most reproduction occurs asexually via bulb division (Jones, 1979). Even though ramps tend to produce plenty of seeds, high levels of seedling mortality are common due to limited seed dispersal and high levels of competition between seedlings and plants already established within the population (Nault and Gagnon, 1993). Due to the compounding effects of limited dispersal and competition, only about 4% of ramp seedlings survive to three years old when they germinate within their parent population (Nault and Gagnon, 1993). For the purposes of forest farming, seedling survival can be significantly increased by simply collecting seeds and sowing them in a new location where they are free from competition.
Ramp flowers are typically pollinated by a variety of small flying insects but are also capable of self-fertilization. Several species of bees have been observed visiting ramp flowers, including sweat bees (Dialictus spp.), masked bees (Hylaeus spp.), honeybees, bumblebees, mason bees, and other solitary bees (Hilty, 2017).
Ramp seeds are primarily dispersed by gravity and simply fall from the seed stalk after ripening. Although, observational studies have shown that deer mice (Peromyscus maniculatus) (Nault and Gagnon, 1993), ants, and other insects (Facemire, 2009) occasionally collect and disperse ramp seeds as well.
Ramps are considered a highly adaptable species and are capable of growing under a variety of habitat conditions. From our introductory discussion about site selection in Chapter 1, we know that the best growing sites are typically located on north, northeast, and east facing aspects. Within these aspects, select sites with a mature canopy of mixed hardwood trees that provide approximately 60%-80% shade to the forest understory and well-drained soils that are rich in organic matter and have a pH ranging from 4.7 to 6.7 (Bernatchez et al., 2013). Unlike the other species featured in this publication, ramps have a relatively high tolerance for soil moisture and are commonly found growing in forested bottomlands and other semi-riparian areas. These habitats should not be overlooked as potentially viable production sites but should be closely evaluated to ensure that the essential habitat criteria are met.
As previously discussed, the presence of companion and indicator plants can also be used to identify suitable growing sites. Species that are commonly found growing in association with ramps or prefer similar habitat conditions include, but are not limited to, tulip poplar, sugar maple, basswood, sycamore, elm, birch, trillium, cut-leaf toothwort, wood nettle, black cohosh, ginseng, bloodroot, blue cohosh, trout lily, and bellwort (Davis and Greenfield, 2001). Keep in mind that suitable production sites can also be found on south or west facing micro-sites where adequate moisture and shade are maintained.
Prepare the site for planting by following the guidelines for wild-simulated site preparation discussed in Chapter 1. Preparations will include removing large sticks and debris that will interfere with your rake; pruning or removing small understory trees, shrubs, or branches to improve air flow and reduce competition; and manually removing non-native invasive species.
To plant ramp seeds using the wild-simulated method, simply rake back the leaf litter on the forest floor to expose a 4’-5’ wide strip of soil. Make the strip as long as desired or as long as the site will allow (avg. 40’-50’). After the strip has been fully exposed, use a hard steel rake to scuff and loosen the top ¼” soil. Sow seeds at a rate of 7-10 seeds/sq. ft. until the strip is fully seeded. After the bed has been seeded, move uphill to start a second row, and rake the leaves downhill to cover the previously seeded bed. Once the seeds have been covered with leaves, gently walk across the bed to help press the seeds into the ground (Davis and Greenfield, 2001). Repeat the process until the site is fully planted or until you run out of seeds.
Seedlings develop best when sown outdoors in high-quality growing sites with fertile, well-drained soils. Sites with good soil texture and adequate moisture enable plants to develop healthy root systems, which can penetrate into the soil 6 inches or more. Seeds that are sown in seeding flats should be transplanted outdoors soon after the roots begin to develop to ensure that the root system does not become constricted and suppressed. If transplanting is not done properly and with care, significant transplant shock or mortality may result.
Ramp bulbs are best planted in the spring prior to breaking dormancy and beginning their seasonal growth cycle. Depending on location, plant bulbs from March to April using a small mattock, soil knife, hand trowel, or other appropriate digging tool. Dig individual holes or planting furrows approximately 3” deep. Place the bulbs in the hole/furrow, ensuring that the fibrous roots are spread laterally and pointing down and leaving approximately ¼” of the bulb tip above the surface of the soil. Then refill the hole/furrow with soil, gently repacking the loosened soil around the bulb. Once the soil is back in place, cover the planted bulbs with approximately 2” of leaf litter.
Bulbs should be sub-divided and transplanted when 8-10 bulbs appear in a clump in order to reduce competition and maintain active growth. When dividing bulbs, transplant them in late summer after the seeds have been collected or in the early spring as the leaves first appear. Replant the bulbs to their original depth, and water immediately if possible, especially if natural precipitation is not expected.
Seed Collection and Storage
Approximately four to six weeks after flowering, the small, three-lobed seed capsules begin to develop. The capsules, measuring approximately ¼ inch long, remain green as the seeds develop through the summer months and turn a straw/tan color as they ripen in the fall. Beneath the hull of the capsules there will be 1-3 small black seeds, measuring approximately 1/8 inch in diameter. Throughout most of their native range, ramp seeds will ripen and be ready to collect by mid to late September.
Freshly collected ramp seeds can be planted directly throughout the fall months or can be stored in a cool, dry place for planting the following year (Facemire, 2009). If seeds are not planted after collection, make sure excess moisture has dissipated from the seeds before sealing in a bag or jar. An easy way to remove excess moisture is to place freshly collected seeds in a paper grocery bag for 24-48 hours or until they become papery dry before transferring to a storage container. If seeds are not dried adequately, mold and spoilage will occur. When properly dried and stored under ideal conditions, seeds can remain viable for up to three years, but germination rates can decline during prolonged storage.
Minimal maintenance will be needed if proper site selection and planting guidelines are followed. Ramps are a naturally hardy and disease resistant species, making most of the interventions common to other forest farmed crops unnecessary. Plantings that are installed in raised beds, gardens, or other unnatural settings may require additional maintenance, such as weeding, irrigation, and annual additions of hardwood leaf mulch. Additions of leaf mulch in both natural and unnatural settings can help to improve soil nutrition, increase moisture retention, facilitate weed suppression, and provide added insulation during the winter months.
Pests and Disease
Septoria leaf spot is a fungal disease that can affect the foliage of ramp plants. Septoria is a largely cosmetic and non-lethal pathogen that causes small circular blemishes to develop on the leaves causing them to discolor. If possible, the infected vegetation should be removed from the growing site to help limit the spread of the disease.
Ramps are typically harvested by digging up and removing the whole plant from the growing site. Whole plant removal is considered the most aggressive harvest method and ultimately results in the destruction of the plant. Whole plant removal should be accompanied by a robust seed collection and replanting protocol that helps to facilitate the recovery of the population. One strategy for increasing the sustainability of whole plant harvesting is to target dense “clumps” for whole plant removal. By targeting the clumps, the large mature plants can be removed, while the small juvenile plants can be replanted and will continue to grow
The cut-stalk method, also known as the “snap” method (Institute for Sustainable Foraging, 2017), is a non-destructive harvest technique that enables the removal of all leaf material and part of the stalk, while leaving the bulb and roots undamaged and intact. To harvest ramps using the cut-stalk method, insert a knife just below the surface of the soil (approx. 1”-1.25”) and cut the stalk just above the bulb (Figure 3). With this method it is important not to insert the knife too deeply and risk cutting into the bulb, which may impact the ability of the plant to regrow the following season or result in unintended mortality.
The leaf-only harvest method is the least-intensive of the three methods described in this publication and can be a viable alternative for certain producers. As illustrated in Figure 4, leaf-only harvesting simply involves the removal of one-leaf (for two-leaf plants) or two-leaves (for three-leaf plants) (United Plant Savers, 2016), and help ensure that plants will re-grow the following season. Leaf-only harvests can be utilized early in the cropping cycle while waiting for plants to fully mature or as a sustainable stand-alone technique.
Establishing sustainable harvesting guidelines can be challenging and will vary between individual populations and growing sites. Based on available research on the harvest and recovery of wild ramp populations suggests that no more than 10% of a population should be removed in a given year, and harvests should be limited to only once per decade to ensure adequate time for population recovery (Rock et al., 2004). Therefore establishing multiple patches and appropriate harvest cycels is recommended.
Washing and Post-Harvest Handling
Ramps should be washed and refrigerated as soon as possible after harvesting to avoid contamination by potential food borne pathogens. Allium species can potentially harbor Clostridium botulinum, a soil-dwelling organism that can cause botulism, a potentially deadly food borne disease (Block, 2010). For this reason, adequate washing to remove soil particles and prompt refrigeration are strongly recommended. To wash large quantities of material, spread plants on a wire-mesh washing rack and spray the bulbs with a light to medium pressure hose. If any residual dirt is left on the leaves rinse under a stream of low pressure water to avoid bruising or damaging the leaf material. Small quantities of material can be washed using the same technique described above or can be washed in a small sink or basin.