Ceiba speciosa - Silk Tree

The silk tree is quite rare in Santa Cruz County. It's a medium to large semi-deciduous tree growing to 30-60' with a spread of about the same. Variable in form, some specimens are very broad while others tend to be more upright. Many examples I've seen south of SC are much wider than the images I have. Trees are unique with a large swollen trunk with prickles, large primary lateral branches upright but also can be going off in odd directions, (one of its common names is palo borracho = drunken stick). Beautiful in bloom. Formerly known as Chorisia speciosa.

Alternately arranged, palmately compound leaves, 6-12" diameter with 5-7 lanceolate to elliptic to oblanceolate leaflets each 3-5" long with slightly serrated margins. Petiole as long or longer than the leaf blade area.

Stems are covered with prickles, not spins, not thorns, but prickles. Usually dense when young, but as the trunk expands they tend not to produce more of them. I fell in love with this tree while attending Cal Poly. It was being grown by the department and I bought one and had it for years, actually leaving it in Petaluma with my in-laws while we went to Pullman for grad school, and it stayed there till they moved.

Flowers are pink with a light yellow or white throat, 5 thin petals, sort of lacy usually borne without leaves.

Fruit are oval to rounded pods 6-8" long opening up to reveal black seeds covered by cotton like hairs. Blooming in fall.

Green bark and stems, becoming gray with age.

Misidentification:

Hardly, with the stems covered with prickles. 

Location:

Aptos:

Corner of Rio Del Mar and Highland - Very nice tree

Capitola
4815 Crystal Ave is a small one.

4440 Opal Cliff Dr, 3 nice ones

Santa Cruz
City Hall has two of them.

Aesculus x carnea - Red Horse Chestnut

The red horse chestnut is a beautiful late spring blooming tree (late April early May). They are medium sized trees with a rounded crown and spreading branches. Generally 25-35' tall with the same spread. The trees are deciduous and a bit messy with flower parts and big leaves falling all over the ground.

This plant is a hybrid, between the large A. hippocastanum and a smaller red flowering buckeye (horse chestnut) A. pavia. You may be looking at the cultivar 'Briotii' which is  generally the form available in the industry however, larger ones in our area all seem to have the lighter pink colored flowers.

Buckeyes and horse chestnuts are in the same genus. Not sure why the different names, but I guess "The" Ohio State University didn't want to be known as the Ohio State horse chestnuts.

The picture below is located on Opal Cliff.

This one is worth looking at just because of the garden and the view. At the end of Oakland Ave. on Depot hill overlooking the ocean.

Foliage is arranged oppositely on the stems and is palmately compound. Leaves are a medium to dark green, and about 8". Generally with 5 ovate to oblong leaflets. The leaflets look more quilted (not a botanical term but the veins seem to be more deeply set in the leaf) than the other horse chestnuts. 

They look really cool unfolding. Young leaves covered with coppery colored hairs.

Stems are stout as are the main laterals off the trunk giving it a nice course texture in winter. Terminal bud is large but not sticky like A. hippocastanum. Young stems are green and often have copper stuff on them from the buds,

Beautiful pink or red flowers in an upright panicle. The cultivar 'Briotii' has larger and dark red flowers as seen in the first image, while the species is second.

Fruits are fun. The seeds are contained in a green fleshy husk with prickles. It was a 3 seeded capsule but only one seed matures. Seeds are the classic sling shot projectile, glossy browns and patterned. Seems that the fruit can be either smooth or prickled. These individual fruits didn't produce any seeds, but you can see the overall shape and surface.

Here are the seeds from a fruit that has a smooth husk.

Trunks are large with smooth bark for years, eventually developing small fissures and often have rounded plates.

Misidentification:
Other horse chestnuts without flowers. These are pink or red, and is a smaller tree with smaller leaves than those of A. hippocastanum, and the terminal leaflet is not obovate. Additionally, the terminal bud is not sticky.

Locations
Capitola
621 Gilroy Dr. ('Briotii')
308 Grand (at the ocean end of Oakland Ave.)

Santa Cruz
4410 Opal Cliff Drive
Broadway near Ocean
221 Windham St is a beauty

Corralitos 

Aldridge Lane County Park has a couple of very nice trees.

Edited 5/24

Aesculus hippocastanum - Horse Chestnut

The horse chestnuts are a moderately fast growing deciduous tree to about 50' by about 40' wide. Often oval to oblong shaped or a broadly spreading habit, they create a very dense canopy and dense shade. Beautiful in bloom and usually great fall color. They also have great flowers early spring. This one is in Cambridge England. They are a pretty old-school tree and I don't see them around our area.

Leaves are opposite and palmately compound with 5 leaflets. The center leaflet is generally quite a bit larger than the others. Leaflets are 6-8" long by about 3" wide, obovate shaped with with a slightly drawn out tip and serrated margins. Veins uniformly spaced off the midrib and deeply set in the foliage. 

When just emerging from the buds, the young leaves (petioles and some of the undersides) have a rusty tomemtum near the leaf blade attachment.

Flowers are very attractive, in upright clusters 8-12" tall. Individuals are white with a blotch of yellow that turns red in the throat.

Fruit is an attractive green leathery husked capsule with sharp spines,  2 1/2" diameter releasing 1 or sometimes 2 brown shiny seeds.

Fall color can be spectacular. Often less that so here. Usually more yellow that orangish yellow in this picture. I am a bit surprised I don't have a better picture of this tree during the fall or in flower.

Stems are large and have distinct leaf scars. Buds are sticky. Leaf scars are large, and you can easily see the vascular traces forming a U.

Bark is grayish brown in small shallow irregular shaped scales when old, smooth and gray when young.

There is a double flowered form 'Baumannii'.

Misidentification: Other buckeyes, at least around here you will find A. x carnea more often than A. hippocastanum. A. carnea has dry buds, not sticky, red flowers, smaller leaves and shorter more rounded habit.

Location:
Aptos - Cabrillo College, by the Sesnon house down the side of the hill towards the creek. Only one I know of.

Edited 5/24