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Rose Care

Garden Director Jamie Colen on growing roses:

Zoning inSeamus shots 032

Our roses begin their season-long bloom at the end of June and continue through the first frost. We have hundreds of varieties so the bloom time is staggered making for a colorful display from June until October. We have found the secret to achieving success with roses depends on the survivability of the plant. Hardiness is defined as the very lowest temperature the plant can take before the cells freeze and burst. Plants are rated by zone hardiness. Zones across the world are designated by the lowest average temperature that is reached. These zones are rated from 1-11 with 1 being the coldest, near the Arctic and 11 the warmest, down near the Florida Keys. You can tell how hardy a plant is by its rating. The seacoast of NH is in Zone 5a, so when we choose roses to plant we must be certain they are suited for our climate zone.

Love planted a rose and the world turned sweet. —Katharine Lee Bates.
 If you choose a rose that is rated for zone 4 you can be sure it is very tough. Even roses rated for our area (5) can be damaged by constant freezing and thawing. By taking measures to ensure that the bush stays at constant 32 degrees and protecting against desiccation and sun scalding, we can help plants survive the eventual thaws and deep freezes throughout the winter. Helping the plant maintain a constant cold temperature is what winter protection is all about. Another very important aspect of a plant’s ability to survive winter is the proper de-acclimation from cold to warm temperatures.

If a rose is to reach perfection it needs protection

A deep snow cover that lasts all winter is ideal protection for roses.  However, its impossible to predict how snowy New England winters will be so we try to create more protection by bringing in extra soil (not taken from the beds).  We form a cone of soil up to 2 feet or so around the base of each individual bush when the ground has just begun to freeze. After the soil pile has frozen, we apply salt marsh hay as a insulative layer to help it stay frozen and to deflect winter sun from warming the soil pile. The key here is to keep the rose bush frozen through winter and keep it from breaking dormancy. However, we need to allow the bush to re-acclimate to warm weather as the soil thaws in the spring by slowing removing the hay and soil. A good signal that the soil is beginning to warm is when the crocus begin to bloom. In the fall, we leave the canes intact and the rose hips on the bushes to harden off and to also supply the plant with a source of water as the temps drop. We simply tie the canes together so the wind does not damage them.

Tending

A deep snow cover that lasts all winter is ideal protection for roses.  However, its impossible to predict how snowy New England winters will be so we try to create more protection by bringing in extra soil (not taken from the beds).  We form a cone of soil up to 2 feet or so around the base of each individual bush when the ground has just begun to freeze. After the soil pile has frozen, we apply salt marsh hay as a insulative layer to help it stay frozen and to deflect winter sun from warming the soil pile. The key here is to keep the rose bush frozen through winter and keep it from breaking dormancy. However, we need to allow the bush to re-acclimate to warm weather as the soil thaws in the spring by slowing removing the hay and soil. A good signal that the soil is beginning to warm is when the crocus begin to bloom. In the fall, we leave the canes intact and the rose hips on the bushes to harden off and to also supply the plant with a source of water as the temps drop. We simply tie the canes together so the wind does not damage them.

Be kind to your soil

2007 roses 014It’s a living ecosystem and needs to be cared for as much as the plants that grow in it. Avoid using bark mulch on rose, flower and vegetable beds. Most annuals and other high energy plants prefer neutral ph soil levels. Bark mulch actually lowers ph levels or mix peat moss into the soil every other year and add dehydrated manure every spring to increase soil life and water absorption. This is also the best way to help soil hold nutrients longer. The idea is to feed the soil, so the soil may feed the plant. The more organic ingredients in the soil, the less you will need to fertilize. For weed control, cultivate the soil weekly with a long handled four-prong cultivator. This promotes aeration and allows the soil to warm up more efficiently. Do not use foliar fertilizers: although they act fast to green up leaves, they do nothing to enrich the soil and do not last long. Many of these and other chemical fertilizers are not absorbed by the plants efficiently, and much of the remaining chemicals run-off into the water table, creating nutrient loading and algae blooms in rivers, lakes and eventually, the ocean.

Water: the lifeblood

2007 roses 087Natural rainfall is best, as rain water contains many nutrients that are picked up as the rain falls through the air.  Irrigation, whether a soaker hose or standard sprinklers, must be done correctly for it to be effective.  Irrigation on grass, flower or vegetable gardens must be regular and deep in times of low natural rainfall.  We suggest at least once a week for one hour per move or per station. Deep watering encourages root growth to go further down into the soil, protecting the plants against drought.

Choose well

The proper selection of the varieties you grow will dictate how much time you will need to spend caring for your roses. Daily care is usually not necessary but it depends on the variety and the number or bushes you choose to grow. There are many shrub-type roses that are disease resistant and have numerous blooms per bush with very little care. However, the flowers tend to be small. Hybrid Tea roses have some of the biggest and most fragrant roses known, with a much longer and larger bloom cycle . They do, however, require more care but are well worth the effort!

2007 roses 086A rose is a rose is a rose

Not exactly! There are hundreds of classifications and many thousands of varieties are available. Roses are typically classed depending on their parentage or history. We tend to see many different classifications of roses incorrectly lumped into the ‘Old Garden Rose’ category, which really consists of many sub-classes, but essentially describes roses that were hybridized before 1867. There are many wonderful roses in this area that are disease resistant, hardy, and are still being cultivated and sold. Some are recurrent (repeat blooming during the season) and some are non-recurrent (only bloom once in early summer). Many ‘David Austin’ roses have been cultivated from recurrent blooming old garden roses and will reward even the beginning rose grower the very first year with many blooms. It must be noted that many tend to have a smaller repeat bloom cycle. Hybrid tea roses (Grandiflora, Floribunda and Climbers included) are surely the biggest classification these days with good reason — they tend to have big, colorful blooms, are highly fragrant and bloom constantly throughout the season.

2007 roses 066Pruning is key and here’s the key to pruning

Pruning is performed in early spring, just as the buds begin to swell. This can be one of the most daunting tasks to the beginning grower. The entire crop of flowers depend on a correct pruning job. With practice pruning becomes very easy once you know what to look for. Bush roses have numerous, thinner canes supporting smaller flowers and generally need less specific and lighter pruning. Hybrid Teas with fewer, thicker canes that produce bigger, heavier flowers will need more intense pruning. Regardless, they all require a similar technique. Start by pruning back one cane at time to where the cane is green, or right above a swelling bud. You will notice that not all canes are green on the outside, some are dark red or brown, but you can identify a living cane by looking closely for a green cambium layer surrounding the pith after a cut. Continue until all the canes are cut back to something green, or living. Now go back and prune out the canes that are thinner than a pencil, saving only the strongest, best shaped ones in order to create and maintain a good shape. Remember, these canes need to be stout enough to provide a strong foundation to support the weight of many roses. Sometimes, you will only find thin canes depending on the age and variety of the rose. This is why we begin pruning by saving everything first, then go back to thin out.

Bugs Be Gone

Insect damage and disease can be avoided by following some guidelines. Simply choose plants that are resistant to certain diseases such as ‘blackspot’, ‘powdery mildew’ and ‘rust’. If you have established plants that are susceptible to certain diseases, good sanitation can help prevent future problems. Clean all fallen leaves up from around the plant each fall and spring and keep dead leaves from accumulating. This will keep fungus spores from infecting the rest of the bush. Protecting the new leaves with a fungicide should be the last option, but may be necessary in certain situations. Insect damage can explode given certain favorable conditions. Aphids feed on the tops of roses near the buds and can simply be sprayed off leaves with a stream of water. Spider mites can be the most damaging single pest to roses. They are found on the bottom of leaf surfaces on lower branches and typically begin severe damage when temperatures climb into the high 80’s and beyond. When infestations are severe, yellow pin hole spots appear and webbing can be found near the base of leaves. Defoliation is rapid. Spider mites do not like moisture, or cool weather, so occasionally spraying the lower leaves during hot periods is a very effective control method. An application of an ovicide (egg killer) can be performed once in the spring on the soil – this is also very effective and safe. Japanese beetles continue to be a major problem but are easily controlled by targeting them when they are grubs. When the adult beetle is present and feeding, dead spots in the grass are usually apparent. This is because the Japanese beetle grubs feed on grass roots just below the soil level in the spring and again after the adults mate, at the end of the summer. Brown and dead spots are created and under severe infestations, entire lawns are killed in a very short time. There are several control products that can be bought at your local garden center. Thorough watering is always recommended after application, so be sure to follow all instructions with these products to the letter!

Hours and Directions

Fuller Gardens
10 Willow Avenue,
North Hampton, NH 03862
(603) 964-5414
Closed for the season.
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