COMFREY (Symphytum officinale)
Comfrey needs to be grown by root division and propagation, so it can be expensive and hard to get hold of, but the benefits it provides make it worthwhile. After you do get your Comfrey, it will spread like wildfire if you let it, so you may want to keep it contained, unless you don’t mind being over-run by it. This provides extra to give away to your friends! It is very hardy but prefers sun and moisture. You can plant a sterile variety if you can get it, otherwise around 6 plants is enough for anyone. Do not plant it anywhere where you are planting other garden plants, or it will easily take over. The deep root system will self-propagate from any small piece of root, but it also draws up nutrients from way down in the soil that are not available to other plants. So, Comfrey has both its good and bad points!
It is very helpful as a companion plant in orchards, as it has long roots and can draw up nutrients from deep in the soil. It will also help prevent weeds growing around your trees. Comfrey is also a great mulch crop for putting under potato plants, to help them fruit well.
Comfrey’s nutrient profile is very impressive. It contains Iron, copper, Vitamin B12, potassium, sulphur, calcium, phosphorus, Vitamin A, Vitamin C, Vitamin B-complex and selenium when used as a garden fertilizer; it releases a good amount of nitrogen as well. The 3 main requirements for healthy plant growth are Nitrogen (for leaf production), Phosphorous (for plant health) and Potassium (for producing flowers and fruit). British Columbia researchers, studying the NPK (nitrogen-phosphorus-potassium) ratio of Comfrey, found that the leaves produce a remarkable NPK ratio of 1.80/0.50/5.30, which is better than manure.
Harvest Comfrey when it is around 50-80cm tall and before it flowers. You should get around 3-4 harvests a year, more in milder climates. You can either pick the leaves, or cut the whole plant off leaving around 10cm of stalk. You should wear gloves, as some people react to it. Comfrey will regrow well each time you harvest it, if you keep it watered and mulched.
To make “Comfrey Tea” – fill up a bucket or similar with water and chop up 2 large handfuls of Comfrey leaves into the water and stir up well. Continue to stir and allow to rot down. The whole process will take a few weeks, but it is incredibly easy. This tea has a bad reputation of being extremely stinky, but we have not found that, maybe we are just used to garden smells! When the tea is finished, water it down to around 50/50 before using as a spray or plant food.
You can also do a no water version, which makes “Comfrey Stew!” Get a large container (one with a tap in the bottom is preferable), and half fill it with chopped up Comfrey leaves. Place a heavy weight on a board of some description on the top of this, to press it all down. As it rots, it will exude a thick brown gunge that you water down around 20:1 before using. This way apparently avoids the smell of making the water tea, but we have not tried it yet.
As a liquid fertilizer: spray on foliage, which is helpful for plants with fungal problems, due to Comfrey’s high copper content. Strain the Comfrey Tea mix well with either coffee filters or muslin/cheese cloth and put it in a sprayer unit for ease of use. Remember to spray not just the top of the plants, but to get underneath the leaves too, as the spray is useful for disease prevention and treatment, as well as fertilizing and any extra coverage increases efficiency. Another tip is to put a little liquid soap in your spray to help make it stick to the plants better.
Comfrey Tea can also be used as a plant food by pouring generously around plant roots. You can then put the remaining rotted leaf matter into your compost to help it break down, or put it around the edges of your plants as extra fertilizer dressing. Just leave a gap from the stalks.
In Russia, Moscow State University Scientists found that Comfrey leaf spray helped prevent powdery mildew spores from germinating on wheat seedlings. This is worth following up on and as I have only just come across this information, we will be trialling using Comfrey tea sprayed on our curcubits in summer to see if it helps them from contracting powdery mildew.
To help activate compost, collect the older Comfrey leaves and a few bunches of younger ones and chop them into your compost heaps, mixing in well and watering. They will help to generate faster decomposition and add nutrients to your compost. This is a real a win-win. You can also add Comfrey leaves to your compost as a layer, just like any other plant matter.
To use as a mulch, pick off the older Comfrey leaves and some bunches of younger ones, and either spread them around your plants and over your garden, or chop them up first and do the same. The more you cut down the leaves, the faster they will break down and provide rich nutrients for the soil and surrounding plants, but the quicker you have to replace the mulch.
As a soil fertilizer, dig in chopped up leaves around plant roots and cover with some soil, or dig a trench and place the Comfrey leaves in the bottom, covering with a good layer of soil.
NOTE: Because of the high nitrogen content of Comfrey leaves, they won’t take nitrogen from the soil as they decompose like other mulches can do, and their high potassium levels are great for any fruiting vegetables and flowers, berries and fruit trees or plants that you want to seed up quickly. Just don’t use the leaves as a mulch or fertilizer near or around root crops or leafy greens that you want to harvest, as they can make them go to seed too quickly.
Comfrey roots for propagation are available by mail-order from Koanga Institute, but you have to wait until spring for them to be delivered. http://www.koanga.org.nz/shop/artichokes-comfrey-strawberries-ulluco-yams-yacon/comfrey-root/