Most ferns begin life as rosettes, and many stay in that form. Others may grow a central stalk. Ferns may benefit from the rosette formation because of the added ability to funnel water to their roots, but they also may gain nutrients from the leaf litter their fronds can trap when in their natural forest environment. Japanese painted fern (Athyrium spp.), which grows in USDA zone 5 to 8; staghorn fern (Platycerium spp.), which grows in USDA zones 9 to 11; bird’s nest fern (Asplenium spp.), which grows in USDA zones 9 to 11; and sword fern (Polystichum spp.), which grows in USDA zones 3 to 8 all keep their rosette formation when mature.
Many garden vegetables form rosettes. Lettuce, cabbage, bok choy and kale are some examples of vegetables harvested as rosettes. But these vegetables are only rosettes temporarily. When they form seeds, they become more shrubby and inedible — called bolting. Because heat triggers bolting of these cool-season plants, these vegetables are best grown in USDA zone 8 during the cooler parts of spring or fall. In higher zones, these crops may be grown in winter.
The rosette formation protects some plants from the cold.
Most succulents that form rosettes maintain that form their entire lives. The rosette formation allows for maximum exposure to the sun while allowing the plants to capture and direct moisture toward the roots. Most succulents come from arid areas where thick leaves allow them to retain water. Many succulents also grow in more temperate areas. In warmer areas, aloes (Aloe spp.) and agaves (Agave spp.), which grow in U.S. Department of Agriculture plant hardiness zones 8 and above, are good examples of plants with a rosette pattern. In more temperate areas, such as USDA zones 3 to 11, you can enjoy the rosette patterns of the hens and chicks (Sempervivums spp.).
Many perennial weeds start out their life as rosettes. These weeds grow in nearly every area of the United States because they are so resilient. Dandelions (Taxaracum spp.), teasel (Dipsacus spp.), thistles and plantains (Platago spp.), among others, form rosettes the first year, and during that same year or the following year they produce seeds. Dandelions and plantains retain their rosette shape even when producing seeds, but teasel and thistles form central stalks before forming their seeds.
When looking through gardening catalogs or on the Internet, you may be confronted with the term “rosette.” Although it sounds like it ought to be the name of a plant, it actually is a description of how a plant grows. If a plant grows in a rosette form, the leaves will radiate from the center stalk either right at ground level or close to the ground. The term rosette is used because the pattern resembles the habit of a rose’s flower. Many types of plant grow in a rosette pattern.
Many perennials begin life as a rosette but progress to become more shrublike. Perennials and biennials benefit from the early rosette formation because it exposes as many leaves as possible to the sun, while maintaining a low profile to avoid being eaten by browsing animals. Examples of perennials that begin life as a rosette are avens (Geum spp.), which grows in USDA zones 5 to 9; bear’s breeches (Acanthus spp.), which grows USDA zones 5 to 11; and blazing star (Liatris spp.) which grows in USDA zones 5 to 9. These perennials often emerge as rosettes and stay that way for the first year, then the following year they grow in a larger, more shrublike pattern.
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Lori Norris has been writing professionally since 1998, specializing in horticulture. She has written articles for the Oregon Landscape Contractors Association, chapters of the certification manual for the Oregon Association of Nurseries and translated master gardener materials into Spanish. Norris holds a Bachelor of Arts from Linfield College.
When looking through gardening catalogs or on the Internet, you may be confronted with the term “rosette.” Although it sounds like it ought to be the name of a plant, it actually is a description of how a plant grows. If a plant grows in a rosette form, the leaves will radiate from the center stalk either right at …
What does an infected plant look like?
It is not recommended – at least not right away. Researchers have discovered that the virus does not survive in the soil, which is great news. But any roots remaining in the soil could still contain the virus, so it’s best to allow a few seasons for those to die completely. It’s also possible that mites that were on the infected plant spread to a nearby rose, which means the disease will be cropping up on those plants in the next season or so.
Instead of planting another rose, we recommend that you replace it with butterfly bush or Sonic Bloom weigela. These plants thrive in the same sunny conditions as roses and provide a similarly colorful, long-lasting, easy-care display through summer.
Rose rosette disease is a condition that causes roses to grow strangely deformed stems, leaves, and flowers. The disease itself is a virus, but it requires a very tiny mite called an eriophyid mite to transfer the disease between plants. Eriophyid mites are so small that they can only be seen under strong magnification.
- Bright red new growth that never turns green
- Very thick stems with excessive thorniness
- Flower buds emerge in tiny, tight clusters
(these are the “rosettes” that gave the disease its name; they are also called “witches brooms.”)
- Flowers that open are deformed and stunted looking
- Foliage is contorted and stunted looking; may also be yellow
A rose that is infected with the disease may have only one of these symptoms, or it may have any or all of them. The symptoms may be confined to just a few shoots or part of the plant, especially at first. Symptoms may appear any time that the rose is in active growth, but are most likely to be seen in the early to middle part of rose season.
Currently, there are no roses that are known to be 100% resistant to rose rosette disease, including those that are resistant to other rose diseases like powdery mildew and black spot. Much research is being done on finding roses that are resistant, and while the outlook is good, it will be several seasons still until researchers can definitively say they’ve discovered anything that is truly resistant to RRD.
- Prune your roses in late winter or early spring. The mites overwinter in any flower buds or seed heads on the plant, so pruning these off your roses in early spring and disposing of them can eliminate any mites that were lurking on your plant.
- Do not use leaf blowers around your roses. The tiny mites are readily blown by gusts of wind, so this can spread them through your landscape.
- Protect roses from prevailing winds with walls or other plants. Because the mites are blown on the wind, shielding roses from the primary wind direction can minimize the risk of RRD.
- Give your roses plenty of space. Plant them so that the leaves of one do not touch the other, as this makes it easier for the mites to walk from plant to plant. It also helps minimize other diseases by ensuring good air circulation, and healthy, vigorously growing roses are always a good thing.
- Control multiflora rose in your area. Invasive multiflora roses are a big part of the rose rosette equation and their spread is partly responsible for the surge in RRD infections. Learn how to identify multiflora rose and look for it in natural areas near your home. It may grow in parks, woods, fields, roadsides, and farmlands and is most recognizable in early summer, when it is in bloom with small white (sometimes pink) flowers. The small red fruits that follow the blooms are also distinctive – removing the plants at this stage will also help minimize its spread. When you find multiflora rose, remove it by digging it up and either discarding it or leaving it in a sunny, dry spot with its roots exposed to dry up. Get involved with invasive plant clean-up days through your local parks or natural resources department, or organize your neighbors or gardening group to spend a few hours hunting it down and removing it. Removing multiflora roses not only minimizes the risk of RRD, it also helps the environment!
- If you have been around multiflora rose or have removed an infected rose, wash your hands, gloves, and clothes before working in the garden. All could have picked up mites. While the virus that causes RRD does not live very long outside of the plant, mites can be present on your shovel or pruners, so wash these off and wipe down with a household disinfectant before working in the garden again. This may seem like overkill, but the mites are so tiny that they can easily hitch a ride on you or your tools.
Are there any roses that don’t get RRD?
Proven Winners – What is rose rosette disease? in Garden Maintenance Pest Management and ColorChoice