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.

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 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