We've got what you need

Silphium perfoliatum


Firstly, what is Sunergy?

Latin name: Silphium perfoliatum

Native to: Eastern and Central America

Sunergy is a low-input, high-output perennial crop which
solves many problems of cropping rotation. It has a 10–
15-year life span and once established is resilient and
reliable, unaffected by any major pests or diseases.

It has a wide range of end uses, including AD fuel,
ruminant feed, fibre for packaging, an ingredient in the cosmetics industry and can even be used as a human food source. It has a complex root structure which acts as a carbon sink, while improving soil health. Moreover, it is a fantastic nectar source for pollinators.

This little yellow flower is the future!

My Journey & Sunergy

“I’m from a practical farming background and have worked within the seed trade for 10 years as a technical sales specialist. I specialise in forage and regenerative agriculture and in agronomy for unusual seed crops”. “My approach to agronomy is to use biological and cultural methods before heading to the spray shed.”

“I discovered Sunergy by chance in conversation with a
colleague and quickly realized I had hit upon something

I’m extremely excited about Sunergy as a crop type,
not only because of its benefits to the grower but for the
impact on our environment and farmland wildlife”

Nick Green, Agronomist

What's Special About Sunergy

Long life span

Durable, reliable and consistent

High output / low input

Suited to wide range of growing sites

Excellent green credentials

Carbon sink

Agronomically does not effect the majority of rotations

Multiple uses

Some Applications for Sunergy

An attractive proposition as an ideal plant for energy in anerobic digestion.
In development for fibre for packaging both paper and plastics. A wide range of uses for plant-based proteins such as cosmetics. Suitable for vegan friendly foods.
A wide range of uses for plant-based proteins such as cosmetics.
Suitable for vegan friendly foods.

A Growers Guide


Silphium perfoliatum, also known as compass or cup plant, is from the Asteraceae family. In the first year of cultivation each plant forms a rosette and develops a strong root system in preparation for second year growth. Between 3 and 20 stems per rosette will appear in the second season, growing to height of up to 3.6m from April onwards. The long flowering period of Sunergy occurs between July and September with each bright yellow bloom approx 6 to 8 cm wide making it a fantastic pollinator. Once harvested Sunergy provides useful, soil protecting, over winter ground cover before recommencing the growing cycle the following season.

Environmental Advantages

Once sown each Sunergy plant will crop, from year two, every year for up to 15 years. The plants provide substantial ground cover which guards against soil erosion while enriching biodiversity. Being a perennial crop there is no soil disturbance which leads to a long term, beneficial increase in the soil microbiome. Sunergy requires very few inputs each year as its complex root structure draws all necessary nutrients from the soil while sequestering carbon. All of these advantages make Sunergy a very sound choice for improving the overall environmental performance of farmland.

Site Selection and rotational position

Another advantage of growing silphium is that it can be grown across a wide range of sites. It will perform well even on more marginal sites where maize may struggle. Fields that are challenging to work with large equipment are also ideal as only a digestate and harvest pass are generally needed each year.

The only sites to avoid are ones that sit waterlogged for very long periods of time. In general, Silphium will reliably produce a crop even in years when weather is inclement as its perennial cycle eliminates the risk of poor or late planting due to erratic spring ground conditions.

In terms of rotational positioning, it is advised but not essential that it does not follow either an Oilseed Rape or Sunflower crop to prevent a potential sclerotinia carryover.

Seed bed preparation and sowing

Well Sown is half grown! Be prepared to put in some effort to gaining a suitable seedbed. The aim is to have a stale seedbed, as weed free as possible prior to planting by way of a pre-emergent application seven days prior to planting.

In the first year, when silphium is in its establishment phase, it is advised that maize is also sown as a nurse crop which is harvested as normal, ensuring that the field is still productive in that year.

There are some sources online which suggest that there is unreliable establishment of Silphium from seeds and that it is better to use high seed rates. Fortunately, due to the quality control procedures we have in place in addition to the use of advanced seed treatment, we have a consistent germination rate allowing us to use a seed rate of 3-4 kgs/ha. Suggested sowing depth is no greater that 0.5cm



As previously mentioned, it is advised that most of the weed control is dealt with before sowing by way of a pre-emergent.

Once sown, in the first year a pre-emergent should be applied. Please get your agronomist to consult with Newtone Agriscapes or use the Agronomy service from Newtone Agriscapes.

This should be sufficient weed suppression until the nurse crop of maize gets established and will outcompete most other weeds.

Once the maize has been harvested the silphium should have sufficient ground cover to prevent autumn weeds, as the soil is not being disturbed there should be less germination of weeds anyway.

Fungal Desease

In a very rare instance Silphium is susceptible to Sclerotinia, normally only after following OSR or sunflowers.

If sclerotinia is found it is advised to harvest early to prevent the formation of sclerotia. If following OSR it may be advisable to spray during flowering. Please seek advice from Newtone Agriscapes if this is deemed necessary.


Monitor for slugs from the offset, it is critical to manage slug pressure until second true leaf is formed.


During the first year, fertilise the maize crop as you normally would.

Approx. 1 kg N is required in the following years to produce 1 dt DM

Following the harvest of maize, Silphium will benefit from an application of digestate. (This will fit within the regulations as you are applying to a growing crop.) We believe that a second application of digestate in early spring will be enough to sustain the crop. Applications must be made early to prevent damage to the stems.

Crop destruction

After the 10-15 years is up Silphium is easily destroyed using glyphosate or any other broad leaved herbicide that will combat Asteraceae species.

It is advisable to follow the crop with a cereal or other gramineous crop so that any volunteers are easily dealt with.



At present, the main use for Silphium is as silage for Anaerobic Digesters. It can also be used for animal feed.

Silphium fibre can be used in packaging, although a UK market for this is still being established. There are also many other applications of Silphium protein being explored, this strengthens our belief that Silphium is the crop of the future!