My neighbor’s rose bush has lots of hips. We’ve never thought about starting roses from seed before, but it has some economic appeal. Is it possible?—DL, R.I.
Answer: Yes, you can start roses from seed. This can be a thrifty, if slow, way to make a hedge of roses.
You should harvest the hips (rose fruit) before they are ruined by freezing temperatures or eaten by birds. In most cases, seeds will remain viable four months after rose petals drop. Shell the hips and separate the seeds from the pulp, using a blender. Place the seeds in a moist soil-less medium (such as vermiculite) in an airtight bag. Refrigerate the bag for 12 weeks, then sow the seeds in small pots of seed-staring mix.
When seedlings appear, place the pots under fluorescent lights in a cool place. As the seedling develop true leaves, move them into deep individual pots. Water them with distilled water and treat them with a fungicide to prevent damping off. Do not feed them.
As the seedlings grow, move them up to bigger pots and in spring move them outside to a cold frame or other protected place. When a plant is bushy and one foot tall, plant it in a well-prepared bed. Two-foot spacing will produce a quick hedge.
Your seedlings probably won’t flower until their second or third year. Their blooms will look like their parents’ blooms if the parents were self-pollinated. More likely you’ll find some variety among the seedlings. Cross-pollination produces some interesting novelties. Rosa rugosa typically show a lot of variability.