Albizia julibrissin 'Rosea' - Rosea Silk tree

A nice dark pink or rose colored cultivar of the standard Mimosa tree. From what I can tell they look just like the species in all aspects except the flower color, so please see the description of the tree in that post.

Flowers are much darker pink almost rose colored.

You will see that some good references consider this a botanical form or forma and not a cultivar.

The RHS considers it a forma
The USDA considers it a variety
Cal Poly considers it a 'Cultivar'

Location:
Aptos
Marlo Ct off Soquel Dr.

Capitola
216 Central Ave

Albizia julibrissin - Silk tree

The Silk tree or Mimosa tree is a fast growing small to medium deciduous tree commonly planted in Santa Cruz. Growing to 30' tall with an upright vase shape to a wide spreading umbrella habit, with horizontally layered branches on which the flowers are borne. Trees bloom in summer. They quickly lose all their foliage in fall and are late to leaf out. If you google Albizia you will see it's most common websites discuss its invasiveness.

Leaves are deciduous, alternate, bipinnately compound, 18-20" long, each of the 20 or so lateral leaflets is also compound with 40 to 60 tiny 1/4" long linear leaflets.

The shade created by the foliage is nice, as is the view up into the canopy.

Flowers are beautiful and one of the reasons people plant these trees. Again, like some others in the Legume family that don't look like peas. The attractive part of individual flowers are the stamens. Individually they are small, borne in large clusters in a branched inflorescence.

Fruit is a pod, about 4-6" long, flattened and tan color. Reasonably persistent.

Misidentification:
In flower not likely, however students have a hard time with just the foliage, looking a lot like Jacaranda mimosifolia. But the Albizia leaf is shorter, as are the leaflets.

Location:
Aptos
421 Clubhouse Dr.

Capitola
1540 45th Ave

Sorbus aucuparia - European Mt. Ash

I saw this tree several years ago and thought it was being taken out, but its still hanging in there. The European Mt. Ash is a small to medium sized deciduous tree with great fall color and bright red-orange berries. Growing 20-40 feet tall and 8-10 wide with an upright oval habit but can be more open and rounded with age. Rarely seen in our area but more common over the hill. This one is multi-stemmed. You can see on the right that its growing pretty well over the neighbors house.

Different tree, in the fall.

Leaves are deciduous, pinnately compound, 7-9" long, with 9-15 leaflets, each about 1-2" long with serrated margins along the upper half of the leaf. Dark pale green upper surface, lighter green below, turning a beautiful red in the fall.

Flowers are white, small, about 1/3", white, borne in 6" wide flattened clusters.

Fruit is a small orange-red pome eaten by birds. 'Cardinal' is a bright red fruited cultivar.

Stems are thick, smooth by summer, with a large terminal bud that is covered with white hairs. Often with distinct lenticels. Trunk is more or less smooth.

Goes by several common names, some have Rowan in them meaning Red head….

Misidentification:
Chinese Pistachio maybe, it actually serves the same function in colder landscapes but has better looking flowers.

Location:
Capitola
419 McCromick Ave

Crataegus laevigata 'Paul's Scarlet' - Paul's Scarlet Hawthorn

Scarlet Hawthorn is a deciduous small tree grown for its spring flower display of beautiful scarlet double flowers. Growing 20 x 15 feet with an upright to spreading dense canopy. Usually some horizontal branches which send up water sprouts. It's not one that you will see unless it's in bloom. This one is at one of my favorite small arboretums, Finch Arboretum in Spokane.

This is why people used to buy them.

Foliage is alternate, simple, 1-2" long, dark green in summer, pale yellow fall color, margins lobed, generally 5 lobes.

On young stems you can find stipules.

Flowers are pink-scarlet double.

Fruit is rarely produced, but occasionally you will find a small red pome.

Stems have thorns, heavy on young stems.

 Flower buds rounded.

Bark is furrowed.

Trees are notorious for producing water sprouts in the canopy.

Misidentification: 

Most likely another Hawthorn, but not in bloom or the Washington thorn.

Location

Aptos

450 At Andrews Dr

417 Dorsey Ave

Santa Cruz

726 Hanover St

Acer ginnala - Amur Maple

I ran into a specimen of the Amur Maple while cutting through the Soquel School. Not at all common in SC. The Amur maple is a nice little tree growing to maybe 20' tall with potentially great fall color. Often grown as a multi-stemmed specimen or can be trained as a single stem. A cultivar called 'Flame' has great fall color.

Sorry, old picture with low resolution, but shows the fall color.

Leaves are deciduous, simple, opposite, ovate shaped, with serrated margins, sometimes considered to be lobed with a prominent central lobe. Leaves are 2-4" long. 

Leaves can be quite variable in size as well as being very lobed or only slightly serrated. Age and rate of growth seem to be the deciding factor, with older slower growing plants showing smaller less deeply serrated margins.

Flowers are produced in spring, light green or yellowish, in chains, slightly fragrant. 

Fruit is typical of maples, paired samaras. The pairs hang almost parallel to each other and one is generally much smaller than the other. In summer they can be bright red. 

Bark is dark gray and usually pretty smooth but as they age they develop some longitudinal furrows. 

Also know as Acer tataricum ginnala.

Misidentification:
Not likely

Location:
Capitola
On Porter St at the Soquel School, near the east end of the campus close to the building. (Gone, removed for remodeling.)

Quercus virginiana - Southern Live Oak

The Southern Live Oak is a nice medium sized broad spreading tree commonly planted as a street tree in SC county. Usually reaching 30' and potentially wider than tall. Seems to be a nice tree. I guess I would be more excited if we had some massive ones like in the south where they can be 100' tall and 150' wide with massive trunks and covered with  lichens. 

Leaves alternate, simple, 1-1/2 to 5" long, variable shaped, from obovate to oblanceolate to elliptical to ovate, just like an oak to be difficult to pin down. Margins can be entire, or lightly spinose but usually rolled under, dark glossy green upper surface lighter to pubescent lower surface. Trees may experience a very short period of deciduousness prior to putting out the new leaves. It happens about the time the buds start to swell.

Male and female flowers separated on same plant, males in long catkins, females small and reddish color some distance from the end of the stem.

Acorns are dark brown, glossy, elliptical shaped 3/4 to 1" long, in clusters.

Bark with reddish brown color in between the shallow squared plates.

Misidentification:
Perhaps Q. ilex due to the non "normal" oak leaf, but these are longer and narrower leaves.

Location:
Capitola
Gross Rd and Soquel Ave intersection - frontage road off 41st


Santa Cruz
7th Ave lots along the side of the road.
2801 Soquel Ave in front of Big Creek Lumber
Capitola Rd in live oak

Soquel
4800 Bridge St - corner of Main

Tilia tomentosa - Silver Linden

The Silver Linden is a large deciduous tree with multiple upright leaders reaching 50' or more with a spread of 30' with an oval outline. Pretty attractive when young as it forms a columnar tight habit. Rarely seen in our area but common in the northern states. There are several variations of this species, one of which is T. x petiolaris (seen below) and called weeping silver linden and a hybrid of the silver linden and some other linden.

 This is a cultivar called 'Sterling'.

The deciduous leaves are alternate, simple, broadly ovate to about 4" long, with serrated margins and a slightly acuminate tip. Leaf base is unequal like other lindens. Dark green upper surface and white hairs on the lower surface.

Stems slightly covered with white hairs as well. Linden buds all look the same with one bud scale larger than the others, looking something like a boxing glove.

Flowers are fragrant, borne in the summer on long leaf like bracts, yellowish green in clusters of 3-7 flowers.  Attract tons of bees. Some confusion exists about its toxicity to bees which can be found in large numbers on the ground below the trees at flowering time. The nectar is to blame. 

Fruit is a dry little nutlet, about 3/8" long and ribbed.

Fall color is a beautiful bright yellow.

Thanks to Leslie Keedy, Santa Cruz City Arborist for pointing this tree out to me.

Misidentification:
From a distance you might see the silver from the bottom of the foliage and think its a silver poplar??

Location:
Santa Cruz
731 Highland Ave (on the Ross side of the house)

Prunus lyonii - Catalina Cherry

Catalina Cherry is a small CA native tree or large shrub growing 10-25' tall. Upright to lightly spreading, they attract birds for the fruit. Considered to be a botanical variety of Prunus ilicifolia by some and a distinct species by others. I have even seen multiple LL's in the name…..

Evergreen leaves are alternate, simple, ovate to broadly ovate, entire or lightly serrated margins, glossy green above 3-5" long.

Stems are green or brown, buds more pointed than P. ilicifolia.

Flowers white, early spring in upright racemes. Look very much like so many other Prunus species in this group but are longer than P. ilicifolia.

Fruit is a red drupe turning bluish black when mature.

 Trunk silver gray colored.

Misidentification:
Prunus ilicifolia as this one does not always have the holly like leaves and the fruit is black not red like the species.

Heres what I have been able to come up with to distinguish these 2 closely related species:
Las Pilitas Nurseries suggests that its very unlikely to find true P. lyonii, most are hybrids.
P. lyonii has larger leaves, up to 5" and mostly entire (no teeth) mostly flat without rolled over margins, thinner and a longer petiole as well as longer inflorescences, up to 5" long.

Prunus laurocerasus is the type species for the subgenus Laurocerasus or the cherry laurels. Others in this group include P. ilicifolia, P. ilicifolia lyonii, P. laurocerasus, P. lusitanica, P. carolinana. They all have flowers that look and smell like these.

P. lusitanica has narrow long leaves with nice teeth, and very long inflorescences.
P. laurocerasus has very wide leaves, except the dwarf cultivars like 'Otto Luyken'.
P. carolinana has smaller leaves and the shortest inflorescences, about 1-2" maximum.

Location
Aptos
Corner of Clubhouse Dr and St. Andrews Dr., both sides of the street on St. Andrews Dr.

Capitola:
Center St and Bay Ave along the property line of the Nob Hill Shopping center.

Santa Cruz
304 Grant St.