Capers: An Unexpected Beauty in the Culinary and Pollinator Garden
Customers and garden visitors are always surprised to cross paths with the caper plants in our display gardens. “That’s a caper? You mean like the jar of little round capers I buy at the store?” Yep, and when looking at this gorgeous plant in full bloom in the summer, it is always a puzzle to figure out what part of the plant is the edible portion for humans. If you are ready to up your game in the garden with an unusual culinary and pollinator perennial, caper is the plant for you
Capers are fascinating in their ancient history. Their use as a culinary and medicinal plant has been documented for at least 2,000 years, and records indicate they have been eaten for 5,000 years or more. Historically they have been used for flatulence and as an aphrodisiac, two very different medicinal uses! There is a bit of mystery as to where capers originated, but North Africa, the Middle East, the Mediterranean Basin and the drier steppes of Asia all have had capers growing for thousands of years.
The primary species that is used for culinary use is Capparis spinosa. The species has rather nasty spines, so the preferred plant in cultivation is Capparis spinosa var inermis, also known as the spineless caper. The plant is low and shrubby, growing 2 to 3 ft tall and 3 to 6 ft wide. It has two requirements – full, hot sun and excellent drainage. In its natural habitat it grows out of rock walls, castle walls, and rocky fields. No soil. If you have been to Italy, France, Morocco, Croatia or many parts of the Middle East you have probably seen the plant hanging down from walls, looking very much like a plant in a hanging basket, without the basket. The plant roots can extend 20 to 30 feet down through cracks in walls and rocks, harvesting tiny amounts of water throughout the drier months. Capers also are nitrogen fixers, which may help to account for their success under this very challenging growing climate.
One oddity about caper plants is that simultaneously the plant will produce flower buds, flowers and fruit during a very long season of about 5 months.
The flowers are quite striking and lovely – given the dry, bleak, hot, drought conditions and lack of anything resembling soil, it seems a bit odd to produce flowers so energy and water intensive. Here in California we find the flowers visited by many species of bees and butterflies, but where the plant is native, the common visitor to the flower are night flying moths, and the single day and one night opening of the flowers allows a longer access for these moths to find food under desert conditions.
It took several attempts at the nursery to understand what excellent drainage means. In this case, it doesn’t mean adding compost or organic matter to the soil. It means growing in rocks, grit and sand.
In the ground we use a low mound of larger rock, with the soil in the cracks between the rock being very sandy and rocky, such as a succulent soil. Our favorite blend is the ‘Ruth Bancroft’ soil blend available in bags from the Ruth Bancroft gardens in Walnut Creek or in larger loads from Contra Costa Topsoil. You can use the mix with rocks or in pots – it will go against every natural inclination you have about planting, but the response of the capers in this lean, poor quality soil is amazing. And in a wet winter, the plant roots will thrive. I lost every single plant I tried to grow in our native soils, even with plenty of compost, but I have never lost a plant grown in gritty, rocky soil.
Capers can be planted in spring, but I find that fall planting in California is much less stressful on the plant. Planting in October is perfect, as the soil is still warm and days are long enough to promote root growth. You will not see any top growth in the fall, but in the spring the root system will be well established and the shoots can quickly put on growth. Capers are usually semi deciduous in Central California, losing their leaves once night time temperatures are in the low 40s. Caper plants are hardy to 18 degrees F. If you live in a colder area you will need to keep your capers in containers and bring them into a greenhouse, cool room or at least protected in a garage. In late winter prune back the top growth by one half to two thirds, to encourage more branching (and therefore many more flowers!). Don’t be surprised if the new growth is very red or purple while the leaves are small, they will quickly grow out of this once temperatures increase.
Capers have thick, fleshy, rounded dark green leaves, which can be finely chopped and eaten fresh in salads. The head scratcher is figuring out what part of the plant is actually brined or pickled. It turns out there two possibilities to harvest – the unopened flower buds and the berries, or fruit of the plant (Capers are categorized as a fruit). The unopened flower buds are best harvested at 7 mm or smaller – this is called a nonpareil caper, and the flavor is slightly sweet, mildly pungent and delicate, with a firm texture. They are tiny and must be harvested by hand daily, dried slightly and then pickled, so next time you buy a bottle or make chicken piccata, think about the work that went into those tasty little morsels.
While I love capers, in the garden I also love the gorgeous blooms of the caper plant.
Large white flower petals, tinged with a bit of pink, long vibrant purple stamens and a single lime green stigma have an exotic appearance. The flowers typically last one day, but the impermanence of the flowers is more than made up for by the huge number of flowers that are produced on a single healthy plant from May through October. After the flower is finished an oblong berry is produced, which can be picked with the stem attached, brined and enjoyed the same way an olive is eaten. Caper berries are often found on antipasti plates, and they are delicious, with a lightly salted, nutty flavor that is excellent with cheese or meat.
Capers are considered to have anti-oxidant properties, be anti-inflammatory, and may improve digestion. They are high in Vitamin C and niacin. They can be high in sodium if you purchase them, however if you grow your own you can more easily control the amount of sodium in your brine. They are MUCH easier to cure and pickle than olives! In general, the brine is a one to one ratio of water and vinegar, with anything from one teaspoon to one tablespoon of salt per cup of brine. You can use white wine vinegar, apple cider vinegar or balsamic vinegar to pickle, depending on your taste. The capers or caper berries are washed several times before brining. Caper berries are usually kept in water for 3 days, with the water changed every day, for 3 days just to remove some of the tannins. Once in the brine you can either water bath or put the jars in the refrigerator. Try them after about 2 weeks to see if they are ready, and they can be kept in the refrigerator for up to 6 months.
Planting a caper plant out of a pot is of course the easiest way to add this lovely, unusual perennial to your garden. If you want to grow it from seed, be ready for a wait! You can purchase seed or harvest seed out of the caper berry as it dries down and splits open.
The seed can be placed in warm water (or tap water) for 24 hours, then take the wet seed, spread them out on a moist paper towel, roll the paper towel up and place in a glass jar with a few small holes punched in the top lid. Label with name and date, place in the refrigerator (NOT the freezer), and set a reminder to take them out in 2 months. Then take the paper towel and open it up so the seed can dry enough to handle it. If you are planting the seed directly outdoors, place the seed back into warm water for 24 hours before you plant. If planting inside or in a greenhouse, the seed can be spread over a very well drained soil (mix about 1 part perlite to 3 parts fine potting soil – we use Pro-Mix HD because it has mycorrhizae which helps roots grow rapidly). Be sure to cover the seed with a layer of fine soil. Put the containers in a warm location, or allow the plants to germinate naturally in pots outside, but you have to keep the pots a bit moist. Then, you wait. Germination can be as rapid as 21 days, but commonly you don’t see much germination for at least a month, and it will be spotty and slow for up to 3 months. The tiny seedlings generally are dark red or purple, but just let them be and don’t add any fertilizer for at least a month after seeding. We will pluck out the tiny seedlings and put in 3 inch pots of very rich soil (again, I never would have thought this was a good idea, it is just by trial and lots of error) like Recipe 420. After 10 to 12 weeks the plants should be rooted in, and can either be planted outside or transplanted into a larger pot. The roots will always grow first, especially for such a drought tolerant perennial. So, from seed to actual plant in the ground, at least eight months! Yes, it’s a long process, but so lovely and delicious!
I have read that plants are possible from cuttings, but we haven’t had much luck. If you want to give it a try, early spring or fall growth will be best for cuttings, and use plenty of perlite mixed with soil as your media. And send me photos of your success, since I have not yet been able to grow new caper plants from cuttings!
How many plants do you need to actually be able to harvest? One healthy plant will give 2 to 4 quarts of caper berries in a season, they really are a very productive and giving plant. A plant will provide you with a fun addition to your pantry, right out of your garden, year after year!
For more information about capers, we have a short video on our website with information about growing in the ground and in containers. And if you are interested in seeing photos of capers growing in their native habitat, please check out our Facebook and Instagram (can we link to both here?) for photos of capers over the next three weeks.
I am off to Puglia, Italy with my friends and gardening pals Stefani Bittner of Homestead Design Collective link to instagram and Alexis Koefoed of Soul Food Farm to scout out sites for a garden and floral design retreat for 2025. I will forward to you . It is a major farming region in Italy, and also filled with ancient ruins, rock walls and dry locations where caper plants thrive. I know, it sounds like SO much work, but I’m sure there will be an Aperol spritz, some delicious pasta, amazing markets and a couple of large bodies of water to swim in, so we will probably get a break or two from work. And an exciting addition to Morningsun Herb Farms class schedule for 2025.