Growing Rosemary

This aromatic herb originates from the Mediterranean coast, and adds a punch of flavor to a variety of dishes. It can be used in jams and jellies, cookies, and pairs well with lamb, pork, or chicken. Its oil can also be extracted for use in aromatherapy.


To help ensure your Rosemary thrives, we’ve put together this how-to video and transcript covering topics like:

  • Glossary of Rosemary terms

  • Varieties of Rosemary available

  • Starting your Rosemary seeds

  • Caring for Rosemary at all stages

  • Fertilizer and/or Mulching

  • Transplanting best practices

  • Companion Plants do’s and don’ts

  • Common challenges and Their Solutions

  • Pests, Diseases and what to do about them

  • Harvesting and storing your Rosemary


Glossary of rosemary terms

CUTTINGS

A plant section from the stem, leaf, or root that’s capable of developing into a new plant. Rosemary is propagated by shoot cuttings.


WOODY PERENNIAL

Plants with stems that don’t die back, which will grow with each passing season. Rosemary plants are woody perennials.



TERMINAL BUD

The primary growing point at the top of the stem, like where a flower opens up. Rosemary is a fragrant evergreen herb native to the Mediterranean.

Growing Multiple Rosemary Plants

Varieties of rosemary

There are quite a few different varieties for you to choose from.


ARP

Rosemary: Arp Variety

Its leaves are light green, has a lemony scent, and is especially cold-hardy.



WHITE ROSEMARY

Rosemary: White Variety

Blooms with lots of white flowers from mid-winter to late spring. It’s also very aromatic and acts as a bee magnet.



PINE SCENTED ROSEMARY

Rosemary: Pine Scented Variety

This type has wispy or feathery looking leaves. It’s a creeping rosemary with small leaves and pale pink flowers that bloom in late winter. It can become a bit out of hand if not pruned frequently, but luckily this rosemary isn’t damaged in any way from pruning.


JOYCE DE BAGGIO (GOLDEN RAIN OR GOLDEN ROSEMARY)

Rosemary: Joyce De Baggio Variety

A variety that’s gold in color. Sometimes mistaken for a variegated (multi-colored) plant, the leaf color actually changes with the seasons. Leaves are bright yellow in the spring and fall and become a dark green during the summer.


BLUE BOY ROSEMARY

Rosemary: Blue Boy Variety

A slow-growing herb that works well in containers or as a border plant, with edible tiny leaves. It’s a creeping rosemary makes a lovely scented ground cover.

  • Similar Varieties: Santa Barbara Another trailing rosemary that’s a vigorous grower – it can reach lengths of 3 feet (1 m.) or more.

  • Spice Islands rosemary A very flavorful variety that grows as an erect, four foot shrub. It blossoms with dark blue flowers in the late winter and early spring.

  • Upright rosemary This variety has wonderfully flavored leaves and dark blue flowers.

Picked Rosemary in a Bowl

Starting your rosemary seeds

  • Rosemary grows as an evergreen perennial in USDA hardiness zones 7 through 10.


STARTING FROM SEED

  • Germination can sometimes be slow and erratic, needing 12-28 days or more. Their optimum soil temperature for germination is 60°F (16°C), and they don’t need light in order to germinate.

  • Once germinated, rosemary is highly prone to damping off. To avoid this, keep watering to a minimum, provide bright light, and make sure it’s well ventilated.

  • It takes about 16-18 weeks to go from seeding to a plant in 4-inch pots.

  • Rosemary doesn’t need any light in order to germinate.


STARTING FROM CUTTINGS

  • Asexually propagated cultivars are best for pot plant production. Take some tip cuttings that are about 3-4 inches (5 – 10cm) long.

  • Remove leaves from the lower half of the cutting before planting it in light, textured potting media for it to root.

  • The cutting should be watered regularly and kept moist, but not wet while it roots. The rooting medium temperature should be maintained between 70-75°F (21-24°C).

  • Cuttings placed under intermittent mist will start to root in 10 days. Your new plants should be ready for transplanting after about 8 weeks.


PLANTING

  • After the hardening-off process, transplant your cuttings to the garden, spacing them 18 inches (45 cm) apart and allowing for 4 ft (1.2 m) between rows.


CONTAINER PLANTING

  • Once your cuttings have roots, transplant them into individual pots about 6-8 inches deep. Pinch off the very top of the cutting to encourage it to develop branches.

Planted Rosemary

Caring for rosemary

  • In this section, we’ll cover everything you need to know: how to water and prune your rosemary, as well as fertilizer and mulch best practices. We’ll also talk transplanting, companion planting, and your growing structure options.

  • It’s important to keep your plants watered in hot weather. When cold weather approaches, you’ll want to mulch around all your plants.

  • If you live in a place that gets severe winters with sustained temperatures that are well below 30°F (-1°C), rosemary plants will have to be brought indoors during the coldest months.

  • If their roots freeze in times of hard frost, your plants will die.


PRUNING

  • Rosemary pruning can be done anytime during the spring or summer up until 4-6 weeks before the first frost. Make sure that your pruning shears are sharp and clean.

  • Blunt or dirty pruning shears can leave ragged cuts that make your rosemary plant vulnerable to bacteria and pests.

  • If you’re looking to reduce the size of your rosemary, you can prune back the overall plant by one- third at a time. Then, wait 2-3 months to repeat the process.

  • If you’re pruning to simply create a busier plant, you can remove the end 1-2 inches (2.5 to 5 cm) of its branches. This will force the branch to split, creating a bushier plant.

  • This technique is particularly helpful if you’re growing rosemary for cooking, since it creates more foliage in a more compact space.


FERTILIZING AND/OR MULCHING

  • Rosemary is not a heavy feeder, but fertilizing in the spring with a fish/kelp emulsion will get it off to a good start for the season.

  • Periodic foliar sprays along with the emulsion will help keep it in great shape. If you’re growing rosemary in containers, either give it monthly feedings of liquid fertilizer, or supplement the soil with controlled-release pellets.

  • For organic rosemary, use an organic fertilizer or fortify your soil with compost. Indoor rosemary plants will greatly benefit from the regular application of fertilizer.

  • A layer of mulch will protect your plants over winter, and you can use materials like grass clippings, hay, or straw.

Fresh Rosemary on the Counter

TRANSPLANTING BEST PRACTICES

  • Transplanting is possible, but keep in mind that rosemary seeds germinate slowly. Typically they emerge after 3–4 weeks and have a low germination rate, so it’s best to propagate cuttings instead.


HARDENING OFF

  • If you do start your seeds indoors, make sure to harden them off first by putting them outside during the day then bringing them in at night. Do this for a few days, and then plant them outdoors.

  • After the process is complete, transplants can then be planted outdoors or in containers.


REPOTTING

  • Unlike many other herbs, rosemary can grow into a substantial plant up to 48 inches (122 cm). To keep your rosemary plant smaller and more manageable, repot during spring into the same size pot.

  • During repotting, prune the roots of your plant to stunt its growth by snipping off about a third of the root material.

  • Then, put your plant back into the same size container with fresh potting material. If you’d like a larger plant, step up the pot size and repot normally.


TRANSPLANTING CUTTINGS

  • After about 8 weeks, your cuttings will be rooted and ready to transplant – you’ll want to select heavily rooted cuttings.

  • Plants can be soft-pinched by hand or scissors at during the transplanting process in order to develop height uniformity, promote upright growth, and to encourage branching.


  • NOTE: Rosemary that’s grown in the ground does not transplant to containers well, so consider growing yours in a container that can be brought inside during the colder months.

Rosemary Being Grown in the Sun

GROWING STRUCTURE OPTIONS

RAISED BEDS

  • These are a great option, just be sure to prepare the soil by removing all rocks, shrubs, weeds and plant debris first.

  • If needed, fertilize as well to supplement the nutrition added from compost or organic matter. If your soil’s pH is too low, add some lime to make it more alkaline.

  • You’ll also want to add about 4 inches of organic matter or compost to the surface and incorporate it well, normally to a depth of 6-8 inches (15 – 20cm).

  • Raised or slightly mounded beds can provide the best drainage for your rosemary.


CONTAINERS

  • If you plan to use containers, make sure they’re 6 – 8 inches deep and have at least one drainage hole.

  • If possible, use high-quality potting soil that’s loose, well-draining and contains a slow-release fertilizer.

  • If you’ve used the same container before, you’ll want to sterilize it with a solution of 1 part bleach to 9 parts water and rinse well before using it again.


COMPANION PLANTS DO’S AND DON’TS

DO’S

  • Rosemary makes a good companion for beans, Brassicas, and carrots. Rosemary often repels cabbage moths, Mexican bean beetles, and carrot rust flies.

DON’TS

  • Avoid planting rosemary near any other herbs aside from sage.

Freshly Picked Rosemary

Common challenges and their solutions

  • There are a few pests and diseases that can potentially harm your rosemary. Not to worry – we’ve outlined them below, plus how to either avoid or fix the issue.


POTENTIAL PESTS

SPITTLEBUGS

Small brown insects that leave little wads of spit on your rosemary plants. They suck sap from the needles and surround themselves with a white, foamy substance. Spittlebugs tend to affect rosemary plants growing outside, but can also become a problem for those grown indoors or in a greenhouse.

  • Solution: Use a strong jet of water to wash away the foamy substance as well as the insects hiding inside.


APHIDS

These pests are especially a problem for rosemary grown in a greenhouse or indoors. They tend to feed in groups on the underside of branches.

  • Solution: Use a strong jet of water to wash them off your plants. Neem oil, insecticidal soaps, and horticultural oils are also effective against aphids.

  • Just be sure to follow the application instructions on the packaging. Oftentimes, you can also get rid of aphids by wiping or spraying the leaves with a mild solution of water and a few drops of dish soap (one variation includes adding a pinch of cayenne pepper).

  • Soapy water should be reapplied every 2-3 days for about 2 weeks.


WHITEFLIES

Tiny, white-colored winged insects that are a particular problem for rosemary grown in a greenhouse or indoors.

  • Solution: Always start by blasting whiteflies with watering hose. This will cause them to scatter.

  • Then, you can spray the leaves with insecticidal soap. You can also try using a mixture of dishwashing liquid, lemon, and water. A good squirt of soap to a gallon of water should work.

  • Only spray this in cooler temperatures, either early in the morning or late in the day.

  • Also, there are a few natural predators that can help control whitefly populations. Ladybugs, spiders, lacewing larvae, and dragonflies are just a few of the may beneficial insects to have in your garden.

Wild Rosemary

POTENTIAL DISEASES

ROOT ROT

Rosemary is very prone to this fungal disease. It will become limp, and any terminal leaves and stems will die off. This is because the roots are no longer absorb and move nutrients and water to the rest of the plant.

  • Solution: Plant your rosemary in well-draining soil, and water it sparingly. Allow the soil to dry before watering.

  • In general, watering once every 1–2 weeks is enough, but it might need to be adjusted to suit your local climate.

  • If your rosemary has root rot already, dig up the plant and prune out any infected roots, then dust with fungicide powder.

  • If the entire root system is black and mushy, you’ll want to destroy the plant entirely.


POWDERY MILDEW

A dusting of whitish, fine spores will appear on all parts of the plant. It thrives in warm wet periods (typically when temperatures are 60-80°F or 16-27°C), and when your plant is in semi-shade.

  • Solution: When you first see signs of this disease, remove all affected parts of the plant carefully, so as not to spread it. Seal up those infected branches in airtight bags, then dispose of them.

  • There are a variety of remedies that can be used to treat the remaining plant, including neem oil and baking soda.

  • An organic fungicide spray or a DIY mixture of baking soda and water can also help to fight the fungus.

  • Just make sure to always test your remedy on a few leaves first before treating the whole plant.


BLIGHT INFECTIONS

They can be both fungal and bacterial, and result in patchy leaf growth and yellowish spots. High humidity, too little sun and a lack of circulation help promote this infection.

  • Solution: Prune your rosemary to increase its circulation, and make sure your plant is in a sunny spot.


LEAF SPOT

This disease can also be both fungal or bacterial. Brownish black spots appear on your plant, and the stems will wilt.

  • Solution: Avoid overhead watering of your rosemary plants.

Rosemary Growing in the Sun

Harvesting and storing

HARVESTING

  • Branches are harvested by cutting the terminal growth (25–30 cm/9.8–11.8 in) before they become woody.

  • Rosemary can be harvested several times in one season, but it’s important to give your plant some time to recover and replace growth before the next harvest.

  • Some varieties are valued for their small flowers, which can be harvested for use in salads.

STORAGE

  • Clippings can either be used fresh, or dried for later use. Fresh cuttings will retain their best flavor for 2-7 days in the fridge.

  • To store your rosemary for longer periods, hang it in bundles to dry.

  • If you’d like a bit of longer storage for your fresh rosemary clippings, wrap them in a damp paper towel and place them in a zip lock bag.

  • Seal the bag and then stick it in your fridge. It should keep fresh this way for up to three weeks.

  • You can also place your wrapped rosemary inside a reusable plastic storage container.



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