Roses (genus Rosa) are one of the many genera of the Rose family (Rosaceae). There are about 300 species of wild roses worldwide, of which approximately 20 grow in the Netherlands and Belgium. These are roses that grow in their natural environment without human intervention and reproduce by seed. In addition, there are several tens of thousands of cultivars grown by man through cross-breeding.
When breeding garden roses, the breeder has very different criteria than when breeding greenhouse roses.
Important criteria in breeding garden roses are disease resistance, floridity (continuous flowering), self-cleaning, fragrance and winter hardiness.
Important criteria in the breeding of cut roses are the number of flower stems per plant, length of the flower stems, the flower shape, the vase life and tolerance to transport.
Disease resistance is less important than with garden roses because growth is more easily controllable in the greenhouse.
This website relates to garden roses.
A generally accepted classification of rose varieties is:
1. Large-flowered roses. As the name suggests, these cultivars usually have large, well-filled flowers that grow singly or in small clusters on the stem. They are propagated by budding wild rootstocks which combines the vigour of the rootstock with the good features of the cultivar.
2. Floribunda roses. These roses flower in large clusters and usually have slightly less filled flowers. This group is also propagated by budding.
3. Polyantha roses. These roses have small flowers in often large clusters. Propagation by budding.
4. Patio or miniature roses. This group usually blooms with small roses in clusters. They are suitable as ground cover. Propagation by budding or cuttings.
5. Climbing roses. These are in fact espalier roses, they do not climb naturally but have to be tied to a frame. Propagation by budding or cuttings.
6. Shrub roses. These roses can be considered shrubs as far as pruning is concerned. They can be propagated by cuttings, which prevents wild growth. We distinguish the traditional roses (wild roses, botanical roses) and the modern shrub (landscape) roses that cannot be distinguished from the species mentioned above, but have sufficient vigour to form a good shrub on their own roots.
The distinction between the groups of roses is not strictly defined. Due to the many crossbreeds between them, the various groups merge into each other.
We also distinguish between rose varieties that flower once a year and those that continue flowering until autumn.
Once-flowering varieties bloom on branches that grew a year earlier, continuously flowering varieties bloom on branches that grew in that year.
Wild roses generally flower once a year; the flowers usually have 5 petals. The number of petals in cultivated breeds varies from 5 to more than 100. The vast majority of cultivars currently offered are continuously flowering. Some climbing roses (particularly Ramblers) flower just once a year, but very profusely.
Outdoor roses are propagated in 3 ways:
Wild roses can be propagated by sowing. The main application is sowing rootstocks that can be grafted. Seeds from crosses are also sown when breeding roses by crossing. Each seed produces a unique plant; through selection, new varieties are bred.
This involves placing a bud with a piece of bark from the rose to be propagated under the bark of the rootstock via a T-cut. Its advantage is that the growth vigour of the rootstock is combined with the characteristics of the cultivar. Disadvantage is that the rootstock can give wild growth, which needs to be removed.
If the cultivars naturally have sufficient vigour, they can be propagated by cuttings. A major advantage, especially for public green spaces, is that no wild growth occurs. Also, for the grower, the cost price of cuttings is lower than that of propagation by budding.
Outdoor roses come in shapes and sizes, scents and colours. When buying roses to plant in the garden, you can choose between bare root roses that can be planted from November to April in frost-free weather and roses in containers that can be planted year-round. Advantage of bare root roses is the price, they are considerably cheaper than roses in container. The advantage of containerised roses is that you can buy them in full bloom and thus immediately enjoy the floral splendour in your garden.
Flowering roses in container can be bought for use on a terrace or balcony. Of course, it is also possible to enjoy the flowers on the terrace or balcony first and plant the roses in the garden after flowering.
Of course you want beautiful, healthy roses that have good resistance to the main rose diseases for your garden.
To be sure about its health, choose varieties with the German ADR certificate or the Dutch/Belgian Excellence certificate.
Whether you like a rose, is mainly a matter of personal taste. At De Rozenhof in Lottum, you can see a large range of ADR and Excellence roses in bloom. Come take a look and make a conscious choice. The various garden centres in Lottum offer a large assortment of ADR and Excellence roses, also blooming in containers.
1. Roses in container for patio or balcony
These roses are usually repotted in an ornamental pot. Choose a pot with straight or inward sloping sides, considerably larger and deeper than the pot in which the rose was purchased. Do not use a pot with convex walls, it is very difficult to remove the rooted plant from it. At the bottom of the pot, add a layer of clay pellets if necessary. Carefully remove the pot from the rose and place the rose in the new pot. Fill with good potting soil.
The fertilization of potting soil becomes depleted and must be replenished before the growing season.
Every 2 years, potting soil must be replaced.
2. Planting roses in garden
Roses love the sun. They grow and bloom best in sunny spots. Partial shade is still tolerated well by most varieties, but with less than 4 hours of sunlight per day, roses are usually not the best option for your garden.
When choosing the colour of the rose, keep in mind that dark colours and especially dark red roses can burn quickly in the sun. So place them where there is shade during the afternoon sun.
Then again, yellow roses are known to be more prone to frost than other colours, but also to bloom earlier.
Make sure roses can dry properly after rainfall or irrigation to prevent infections with fungal diseases. So plant them well in the wind, but not in a draft.
Preparation of the soil
The rose is a lime-loving plant. It is important that your soil is suitable for keeping roses in terms of acidity. The ideal pH value is between 6 and 7 for sandy soil and between 6.5 and 7.5 for clay soil.
If the pH is too low: apply lime.
If the pH is too high: sprinkle peat.
You can have the pH value tested free of charge at most Boerenbond and Welkoop stores. You can also test the pH yourself; test kits are available at the higher end garden centres and from various online providers.
If you want to plant new roses in a bed where there were previously roses, there is a chance that the roses will grow poorly due to infestation by root nematodes (soil fatigue).
There are three remedies:
The planting distance in beds depends on the height and width of the chosen variety and is 40 to 60 cm for most varieties. Please inquire in advance at your purchase address or on this website [with a link to the encyclopaedia].
Planting container roses outdoors
Planting bare root roses in the open ground
Bare root roses can be planted from November to April in frost-free weather. The best time is November-December, so the plants can make new roots before winter.
If you cannot or do not want to plant the roses right away, you can ensilage the roses by digging an oblong trench, in which the roses are loosely spread out next to each other, the roots covered with soil. In case of severe frost, cover them, e.g. with fleece.