Rosaceae: Rose Family — Roses

Plants in the Rose family include many of our best-loved ornamentals and fruits.  The flowers usually have 5 petals, 5 sepals and numerous stamens, attached to a saucer- or bowl-shaped hypanthium.  Often the oval leaves are toothed, and there is a stipule at the petiole base.

California Wild Rose – Rosa californica

Blooms:

Feb–Nov

Plant Height:

0.8–2.5 m

Flower Size:

Large

Origin:

Native

Habitat:

Generally moist places, especially streambanks

Notes:

Happily, this beautiful flower is very common.  In addition to the moist places it favors, it is sometimes found in open dry places.  The flowers are larger and paler than the other native roses, and its leaves are also larger, pinnate with 5–7 toothed leaflets.  It is most easily distinguished by its stout, recurved prickles, and by the fact that the sepals are persistent, i.e. they remain attached to the hip.  The flowers have 20–40 pistils.

Wood Rose – Rosa gymnocarpa var. gymnocarpa

Blooms:

Apr–July

Plant Height:

0.5–2 m

Flower Size:

Medium

Origin:

Native

Habitat:

Shaded woodland

Notes:

This is less common than California Rose (Rosa californica, see above), and it has smaller flowers (petals 8–12 mm long).  They are usually deep pink to red, with 5–10 pistils.  Leaflets (up to 9 in number) are also smaller.  It has numerous prickles, which are slender and straight.  Its sepals are deciduous, i.e. they fall from the hip as it matures.  The hypanthium is only 1.5–2 mm wide at the base of the petals.

Pine Rose – Rosa pinetorum

Blooms:

May–June

Plant Height:

0.5–1 m

Flower Size:

Medium

Origin:

Native

Rare or endangered?

Yes – 1b.2

Habitat:

Shaded pine and redwood woodland

Notes:

This is a small, rare rose.  Like Wood Rose (Rosa gymnocarpa, see above), it has smaller flowers than California Rose (Rosa californica, also above), and prickles that are straight and slender.  The flowers are a little larger than Wood Rose (petals 15–20 mm long), usually pink to red, and with more numerous (10–20) pistils.  The hypanthium is also broader, 4 mm wide at the base of the petals.  Leaflets are generally nor more than 7 in number.  Its sepals are persistent, i.e. they remain on the hip as it matures.  This is a problematic species, pure (non-hybrid) forms are uncommon.

Sweet-brier – Rosa rubiginosa

Blooms:

May–Aug

Plant Height:

0.8–3 m

Flower Size:

Large

Origin:

Europe

Habitat:

Escape from cultivation

Notes:

This forms a large shrub or thicket with large, rich pinkish-red petals (10–20 mm long).  The flowers have 20–45 pistils.  The sepals have toothed lateral lobes, unlike the native roses which all have entire sepals.  Both leaves and inflorescence are noticeably glandular.  Prickles are few, thick based, curved and compressed from side to side.