Rosemary  GeneralIn recent years Rosemary has started becoming a popular holiday plant in many parts of the country. With its wonderful aroma and the upright nature of many cultivars, coupled by their ability to be pruned and shaped into a Christmas tree shape it's no wonder. Rosemary, for many people, conjures up many pleasant memories with its stimulating, yet relaxing scent. Most of these upright forms can be decorated much as a conventional tree but on a much smaller scale. Actually, after thinking about it, here is a holiday tree that fills your home with the pleasant scent of Rosemary, can delight your eye with the glittering sights of Christmas, flavors your dinner and relieves a great many ailments. Some upright forms can reach up to 6 feet tall with time. Therefore, I would have to say Rosemary is indeed the perfect Christmas tree! Rosemary is an amazingly easy plant of the mint family to grow and will tolerate just about everything except very cold temperatures and wet feet. It has the ability to be shaped and trained into artistic shapes like topiaries and with more and more hybridizations occurring, this amazing plant is steadily moving northward as an important garden element that can remain in your garden outside with care. Varieties are being offered already that will survive winters as far north as zone 6 and with some trickery on your part and the use of "microclimates", you can even squeeze in a zone 5 occasionally. However, rosemary is such a delightful plant, I can't see being without a pot or two indoors in the winter and yes, you'll see it sporting its Christmas colors around our house at Christmas time. Light Rosemary is a plant of the hot, dry climates of the Mediterranean region and enjoys full sunshine for at least 6 - 8 hours per day. However, if you live in an extremely hot area of North America, Rosemary will benefit from afternoon shade. Indoors, place the plant in a sunny south window or provide supplemental lighting with plant lights. Temperature Rosemary is tolerant of high temperatures, however, it will not tolerate extreme cold. Cultivars have been developed that will take temperatures down to 10 degrees F and at least one boasts of being able to withstand colder, but if you expect temperatures to regularly dip into the single digits, it is nest to bring the plant indoors. As a general rule, it is best to bring all Rosemary's indoors for the winters if you live in zone 5 or lower and most will not survive colder than zone 7 or 8 outdoors. Rosemary should have its roots covered with a quick draining mulch in all but the most northerly areas in order to keep the roots cool through the summer months. I generally would recommend mulching with dulled straw, pine straw, bark mulch or even white sand whenever the soil reached 75 degrees F in the summer (another handy use of a soil thermometer  ). Water Rosemary is a plant that tolerates drought, but will do best if watered thoroughly whenever the soil becomes dry 1/2 - 1 inch down in the soil. A moisture probe is a handy, simple and useful tool to keep around for this task. Over watering is the biggest downfall of Rosemary and to much water will cause the roots to rot quickly. If Rosemary is grown outside during wet weather, it is best to either keep it in a well drained clay pot or mound it up in the garden so it is elevated somewhat and provide good drainage. Water usage will be much less during the winter months so use care when watering during the winter or cloudy days. Fertilizer and Feeding Rosemary is a plant of meager fertilizer needs but does require some supplemental nutrients for optimal growth. If you will top dress with compost every month or six weeks if planted outdoors, this is usually all the supplemental food needed. If grown in a container, you can add additional slow release organic fertilizer about once per month at 1/2 strength or if your garden soil is particularly sandy or poor. Rosemary will grow best in a slightly alkaline soil of 8.5- 7.5 pH so test your soil regularly and add lime as needed. Avoid using processed lime as this can burn plants. Wood ashes may also be used in small quantities and worked into the soil, but keep them out away from the plant as they to can burn plants. A word on lime is in order here and applies to all gardening efforts. Garden lime takes time to be effective and works slowly, normally about 3 months. Garden lime is generally a bi-product of mining limestone for gravel and is usually available as a finely crushed rock "dust" and can normally be found in several different "grades" of fineness. Generally, the finer the dust, the quicker it starts acting. Savvy gardeners will often mix both fine and coarse lime dust in order to get a quicker reaction and yet have the finished pH level occur over a longer period of time. In this way, you get fairly quick results with a long term benefit without the risk of overdoing it. Soil Rosemary is not picky about soil, but as stated before, it does require excellent drainage. Therefore it is always best to incorporate compost and sand deeply into the soil before you plant outside. Rosemary has deep roots and thus you should make every effort to improve your soil as deeply as possible. Rosemary does no like to be disturbed once established, so if you are planting in a permanent spot outside, try to take into consideration the amount of room the plant roots will need once the plant is mature. Successful gardeners who regularly grow Rosemary outside do not consider 2 feet to be to deep to improve the soil and therefore will often plan on improving the soil a foot or two and then build a 1 or 2 foot tall raised bed around this area to be filled with good draining soil. I have not found this to be necessary unless I have a drainage problem or extremely heavy soil. In this case it is of real advantage. However, I do like the idea of raised beds for herb gardens in general because a great many of the herbs commonly used are natives of dryer climates and must have good drainage and warmer soils. Potting Rosemary, as stated earlier does not like to have its root disturbed any more than possible. Therefore it is best to choose pots that will allow the plant to grow for at least a year and preferably two without needing repotted. When I repot Rosemary, I generally like to upsize 2 inches all the way around the root ball rather than the traditional 1 inch. What does this mean? In traditional repotting methodology you normally go up one pot size, but with plants like Rosemary, I prefer to go up 2 pot sizes and repot less frequently. With proper care, there will come a time when the pot will grow to large to handle with many Rosemary's, particularly the upright cultivars. When this happens you will need to either Root cuttings of the plant and start over or "root-prune". To root-prune the plant, remove it from its pot (in an area where you have a lot of room to work and preferably on a tarp) and using a saw or machete (an old hand saw works really well, sawing from top to bottom), cut off approximately 2 inches of the outside of the root ball all the way around (place this in your compost bin) and repot it back in the same pot with good quality potting mix that drains well. As with all plants that you root prune, you must bring the top growth back into scale with the roots. Therefore selectively prune off approximately 1/3 of the top growth. Do not sheer it like a hedge. Place the plant in a semi-shady location (a little morning sun only) and water sparingly until new growth begins then gradually move it back into full sun and resume regular watering. Because Rosemary likes good drainage, porous clay pots work best and avoid dark-colored pots as these absorb to much heat from the summer sun. Blooming Rosemary normally blooms in late spring to early summer (May and June) with tiny flowers in shades of whites, pinks and blues. The blooms are born on new wood from the previous year, therefore any pruning is best done right after flowering. Both the the leaves and flowers are edible and while Rosemary is not particularly grown for its flowers, many cultivars bloom so heavily that they are quite showy in bloom and will sometimes look like a cloud of color from a distance. Dormancy Rosemary does not have a dormant period, however it does grow more slowly in the winter months when the light levels are lower unless supplemental lighting is used. Propagation Rosemary is propagated either by sowing seed or by rooting cuttings (slips). Rosmarinus officinalis is the species normally always offered as seed and while this is a great Rosemary, if you wish to have other cultivars, you will be forced to find these from nurseries or order on-line as rooted cuttings. Rosemary is generally not a good herb to propagate from seed because the germination rates are very low (generally about 15%) and it has a bad tendency to produce a lot of variables. It also requires warm soil (75 - 80 degrees F) and very long germination periods of up to 3 months. However, with that all said, it can be fun to try sowing a packet of seed to see what you come up with. You may find a new cultivar produced that has qualities that you like very much. If you want the best success at producing new plants, your best bet is to root cuttings. And if you want copies of a particular favorite, then you have no choice but to start cuttings. This process is called cloning or vegetative propagation in the plant industry by the way. To root your own cuttings, it is best to take woody tip cuttings in late winter or early spring (March and April) that are approximately 3 inches long. Strip the leaves from the bottom half of the cutting. Dip the cut end into a rooting hormone and then insert this into a mixture of equal parts perlite and peat moss (preferably screened). I prefer to use 1 1/2 inch cell packs in a tray with a clear dome lid and one cutting per cell because the cuttings will need potted at variable times. Mist the cuttings in well to settle the media and cover with a clear covering to hold in the humidity. The containers should be kept in a location of bright light with little direct sun and warm (75 - 80 degrees F) until rooted or new growth begins. Open the container and mist the cuttings occasionally to keep moist. From experience, rooting will take from 4 - 12 weeks and rooting will not occur all at the same time. That is why I prefer the cell packs so that I can remove the individual cuttings as they are ready to be potted. At this time the cuttings are ready to be potted into individual 3 inch pots. Using a thermostatically controlled heat mat will speed up the rooting process and make the process more uniform. An artificial light garden is an excellent place to root your cuttings if you do not have a hotbed or greenhouse and if equipped with heat mats, will give you full control of the process. the Hillbilly Gardener Back To Top | 
