How to Grow and Care for Rosemary
Last Updated on May 8, 2024
Salvia Rosmarinus or Rosemary is a perennial plant. Provision of warm, bright, and dry conditions is a perfect set of mix for the plant to live for years. With its mind soothing aroma it is used for culinary and medicinal purposes. Rosemary has a moderate growth rate which remains almost dormant in winters.
It has pine like needle leaves that are green in color. The stems are woody and erect. In late spring the plant produces clusters of purple, blue and white flowers depending upon its variety. The plant is drought tolerant so, does not need watering on every alternate days.
Best Time To Plant Rosemary
Spring is the season for its bloom. So if you are trying to propagate this plant in your house indoor, place it near the south facing window. However it loves to be planted outdoor as warmth of the Sun, natural humidity level and even temperature are the favorable conditions for this plant to attain its maximum growth.
Zone 8,9, and 10 are warmer and are considered ideal for growing Rosemary. These zones have mild and shorter span of winters and longer period of summers. So, it remains evergreen in these regions and lasts throughout the year. In these areas the plant will grow around 12 inches in one summer.
Zone 5 and 6 have comparatively mild winters. In these regions you can bring your Rosemary indoors to protect it from harsh winter nights.
The Site To Grow Rosemary
Choose the spot where direct sunlight of maximum 6 hours can hit your Rosemary. Make sure that the spot has excellent ability to drain excessive water. Besides, it must not be planted near the shady trees as it will stunt its growth.
Rosemary Plant Care
Light
Direct sunlight of maximum 6 hours is required by Rosemary to grow. Areas which are warmer have shown optimal growth even up the month of December. But in colder areas, drop in temperature below minus 20 degrees Centigrade is a time when u need to bring your plant indoor. Use of grow bulbs in cozy cloudy days may help in providing the plant enough light to perform its growth functions.
Soil
Rosemary has reacted well when compost made soil is used to give it a kick start. The soil must have PH in between 6 to 7.
Water
Rosemary never minds if you not water it for days. Use half knuckle test if you want to predict the thirst of your plant. If the finger comes up dry it means that it is time to fetch your plant with water. However water only to make the soil moist but not cloggy.
In winters it can go without water for 10 to 12 days. And in summer watering it once a week is required. Make sure to water the soil and not the foliage.
Temperature and Humidity
Being a heat tolerant plant Rosemary can sustain the temperatures as high as 80 degrees and as low as 20 degrees. Similarly, low level of humidity can positively contribute in giving your plant a healthy life.
The ideal humidity level for Rosemary is 45 to 55 percent. Do not choose the area where cluster of plants are grown as it may suffocate your Rosemary. This will effect the air circulation and rise the level of humidity that may results in root rot.
Fertilizer
Rosemary if provided nitrogen based fertilizer biannually will improve plants foliage and strengthen its roots. But be careful that overfertilization can decay the plant.
If the soil is already rich in nutrients there is no urge of using fertilizer. And avoid using it in winters.
Harvesting Rosemary
The plant can be harvested at anytime of the year. But, Spring is the time when its leaves have best aroma and taste. You can pick around 3-4 inches stem from the tip. Its leaves can be dried by hanging its stems in a well ventilated dry place and later on can be pruned on drying for preservation.
Growing Rosemary In Pots
Rosemary is an invasive evergreen woody herb. If you want to confine its growth, plant it in a pot. Even in frosty winters it will be easy for you to bring that pot indoors to protect it from harsh weather.
How To Propagate Rosemary
Propagation of Rosemary via seed
Although this method is not recommended, as growing Rosemary from seedlings is a slow process. In fact, the plants it produces takes very long to get mature. Some of them not even germinate.
If you want to grow Rosemary using its seeds. Follow the process below.
Keep in check the frost date of your area and get yourself prepared before.
Use potting mix made of 4 parts of compost, one part vermiculite, one part perlite, and two parts of peat moss.
Soak the Rosemary seeds for 24 hours before placing them inside potting mix.
Add seed-starting mix in a tray and disperse them at a distance. Put seeds on the soil mix and further add a layer of it on the seeds.
Now cover the tray with a plastic wrap on it. And place this tray in indirect light.
When you observe the seedlings are around 3 inches above the ground, this is the time to remove the plastic wrap.
Now put the tray in a place where direct sunlight can reach.
Move the seedlings to the planter in which you want to plant it.
Propagation from Cuttings
This is most widely and effective method to grow multiple Rosemary from your existing plant.
Cut a mature stem that is 3-5 inches long.
Prune the leaves from the lower part of the stem.
Use transparent narrow neck container so that only lower part of the stem is dipped in water.
Add rooting hormone to help the stems generate roots.
Make sure to place the container in indirect light while the roots are propagating.
When you see tiny roots coming out of the stem’s lower part. Plant the stem in a potting mix in a pot that has fine drainage holes in it.
Be careful that the pot must not be containing any soil in it.
Now place this pot in a warm place where indirect sunlight can reach the pot.
Mist the potting mix daily to make sure the cutting is getting enough moisture to grow.
After 3 weeks gently pull out the cutting. If you find a resistance it means that roots have made their firm hold in the soil. Resistance is also an indicator that it is time to transplant this cutting in a planter.
How To Repot Rosemary
Rosemary is a root bound plant. Its pruning leads to stimulation of new stems and increase root production. So it is recommended to repot your rosemary in one size up planter for its better growth.
Make sure to use potting mix with perlite in it. It will give a loosen effect to the soil and improves circulation of air in the roots.
Repot it once every year in the spring. Do not repot it in the dormant period.
Pruning of Rosemary
Just like other plants pruning your rosemary positively contributes in your plant’s health. As it will give boost to its growth and will also help new stems to originate. Keep in mind that you do not cut more than one third of the plant as it will give shock to the plant and it may also become a home for pests and diseases.
Tips For Pruning
Do not prune your plant if it is already struggling through a disease.
Secondly, cut off the dead parts of the plant using sterilize scissors or hedge shears. They can also be used to create elaborate topiaries as well as to cut dead shrubs.
Trim in the spring season only when the plant is in its growing phase. Doing it elsewise will pose serious threat to its health. It may cause roots to decay and it may invite pests infestation.
How To Care For Rosemary In Winter
Rosemary needs frost protection. Specially in regions where temperature falls below 30 degrees Fahrenheit. Bring the planters indoors or under the shelter so that your plant may not get frost bite.
If you have planted Rosemary in garden borders, use frost protection row covers as they can maintain temperature and protect the plant from frost.
Similarly in winters if you have placed your Rosemary inside the house then it is recommended to put it near south facing window where it can acquire maximum sunlight.
Do not water your plant frequently in winters. As the evaporation rate is also low in cooler days. So water only when you observe outer layer of the soil is drying out.
Also use mulch to provide insulation to the roots in winter. Use compost, pebbles, or gravel for maintaining ideal environment for your Rosemary to sustain harsh winters.
Common Diseases in Rosemary
Powdery Mildew
As the name indicates powder like fungus scatter on the leaves. This is due to the less humidity and poor air circulation. Your plant might be suffocated in the company of other heavy and shady plants that is making your plant infected by this disease.
This is not a threatening disease but it may weaken the roots over the period of time.
Prevention
Isolate the infected plant to the place with better ventilation.
Change the watering regime.
Fusarium wilt
This is a soil borne fungal diseases in which plants leaves will become yellow in color and starts wilting. It targets plants vascular system and blocks the passage of nutrients and water to the upper parts of the plant.
The main reason of its spread is infected tools and soil. Once it cultures, it stays for extended periods of time and hardly eradicates.
Prevention
Always use sanitize gardening tools to reduce the risk of infection.
Root rot
Leaf spot
Pests
Rosemary Beetles
Aphids
Rosemary Leafhoppers
Rosemary water