Not all roses produce seeds, some are infertile. These can be reproduced only by vegetative means. If it were not for the continuous intervention of man, they would already extinct. Fruits are called "hips".
The roses ripen their seeds in different eras.
Some seeds are ready and will be collected in July, others in August, others in November. For all we will have to wait for February to be sown.
The seeds of roses need four conditions to germinate:
- vernalization
- the temperature
- humidity
- oxygen
The vernalization
The seeds of roses have within them a protein that prevents germination. This protein degrades and the seed can germinate only when subjected to temperature changes. In fact, the seed must "feel" that autumn has arrived, winter has passed, and spring, the best time to be born, has arrived.
It is therefore necessary to stratify in November our "hips", collected at different times, in a container of sand, with drainage holes. Then we have to leave them outside, at the mercy of the weather, from November to February, protecting them from mice that have a sweet tooth, with a net of metal.
In February, the hip will be undone and the seeds ready to be planted.
HIPS
The temperature
The seeds, to germinate, need a minimum temperature of around around 6 degrees. In February, in many areas we can have it outside. Or in a garage or in a basement.
The moisture and the oxygen
The substrate in which to give birth to our roses must be able to retain the moisture and to circulate the oxygen. A mixture of 50% peat and coarse neutral sand is what you need. In the market you can find substrates studied for seed germination.
For germination of the seeds light is not necessary.
The phases of sowing
- Holding the seeds soaked in water for 24 hours
- Fill a container with the mixture
- Press the mixture with your fingers on the sides and bottom
- Remove excess compound with a vertical tablet
- Press the mixture a bit with the same tablet
- Place the seeds at 5 cm distance from each other
- Cover the seeds with half a centimeter of the sifted mixture
- Label with the name of the rose and the sowing date
- Water from above with a watering can (in form of rain very fine)
- Cover the container with a glass plate, to keep it warm and humid
- Spread on the glass a sheet of newspaper, to minimize temperature fluctuations.
The development of the seeds
Seed germination will start after a few weeks, typically from 5 to 7, and will continue until the beginning of summer.
- As soon as the seedlings appear, remove the sheet of paper and the glass plate, place the container in a well lit area, but not in the sun.
- Spray the plants with water regularly, but do not soak the soil.
- Give a fungicide to prevent the onset of rot.
- Freeing each plant from the soil (with a punch) and gently lift her by the cotyledons.
- Replanting in a jar of 7-10 cm from the side, in a compound lightly fertilized.
- Water the pots and keep them bright and warm, not the sun.
Some in May will begin to make the first flowers.
When you see that the seedlings were stiffened, usually around May, you can pot them in a bigger container or if you prefer in the ground.
Gently, place an open hand on the jar, passing the stem between your fingers open. Pour the jar with a few taps and make sure you pull the root ball without breaking it.
Replant immediately and watering. Crucial at this stage will not break the sod.
In November, it is necessary to make cuttings of your roses. This is to avoid losing them, because one of your plants may die. Vegetative propagation (cuttings or grafting a gem) will allow you to have identical copies of your new roses.
EDIT @Patrick
Yes, few, small, but yes, that seeds sown in February, in May will flower. The street of seeds is sometime very long and slow, you sow in February seeds that you collected in July, almost the year before. You need a long waiting and a hard work before you can grow your seeds. But actually when the seed grows, goes some quicker.
Of course, not all your plants will give flowers, but you can see the first ones yet.
Remember that the roses come from the seed are all different from each other and from mother plant. That means that the flowering time changes also. That's why I say to take some cuttings.
Ones will give flowers yet. Others will be late. Surprise of natural germination =)
EDIT II @ Bamboo
Of course, seeds can carry genetic characteristics of any type, derived from the mixing of chromosomes. From seed you can achieve anything.
But the questioner is probably a curious gardener, who likes to experiment. Similarly those who ask that result may have grafting cuttings of apples and pears on the same stem.
If you want true roses, you have just to proceed by grafting.
=)
EDIT III
Link to Museum-garden of old rose, which often gives me information. Please note that the Museum is in Italy, so the text is written in Italian. However, it includes a lot of great pictures and diagrams which can be helpful to people who don't speak Italian.
