Plant Guide to
Carlsbad Seawalk (Beach Sidewalk), San Diego County

This is a working list, about which I make no guarantees at all until I officially release it. Use at your own risk!

Some of the identifications below were based on dead plant remnants from the previous year. I've never yet covered this "trail" except in October and November.

Introduction and Explanation of Plant Trail Guides

Introduction
Highlights of This Trail
Fieldwork Dates and Summary of List Changes With Time
The Plant Guide
Comments On Specific Species

Introduction

This is an unusual "trail", in that it is actually a concrete sidewalk along Carlsbad Blvd. that borders the cliffs on the top, and a return sidewalk at the base of the cliffs just above the beach. Somehow, fortunately, probably due the highly eroded cliffs, a pathetically small remnant of native plant habitat was left virtually intact between the sidewalk at the top of the cliffs and the sidewalk at the bottom of the cliffs, and became part of the State Park here. The bottom sidewalk borders the beach, which is a sandy beach if there has been recent sand replenishment, or made mostly of cobbles otherwise. The guide below begins at the top sidewalk, and returns via the lower sidewalk, hence all the plants are on your right. Most species planted in sidewalk openings are not mentioned in this guide.

The sidewalk at the bottom of the cliffs is actually on top of a monstrous sea wall, 40 feet tall, braced by steel beams that were sunk 25 feet below sand level to tie in with underlying bedrock. Sheets of steel that run all the way to the top of the wall connect the steel-beam supports. This is one honking structure, most of which is not visible at all!

The sea wall was completed in 1988, after the storms of the early 1980s battered the California coast. The official name of the project is The Carlsbad Boulevard Seawall State Erosion Control Project, but most people just call this the Carlsbad Seawalk or simply The Seawalk.

The 10 foot wide sidewalk at the bottom of the cliffs is bordered by 2 foot wide walls on both sides which rise 4 feet above the sidewalk. This conveniently places the plant species at eye level for this lower sidewalk. The sidewalk / sea wall is 4,400 feet long, ending at Agua Hedionda Lagoon.

The upper sidewalk was created as part of the sea wall project, and its charm was enhanced greatly because Carlsbad buried the utility poles.

This set of sidewalks is very popular with walkers and joggers, and also with sunset viewers. The sidewalks are aesthetically very pleasing because they follow the undulating coastline. In fact, the sea wall turned out so beautifully that it was featured on the cover of Sunset magazine in 1988 and has won numerous architectural design awards.

The focus of the guide is the area between the upper and lower sidewalk, which is owned and managed by State Parks. Prior to the construction of the sidewalks, people tramping down the slopes to get to the beach destroyed much of the native vegetation that was there. This disturbance has now largely stopped, and some natives are coming back.

There was a serious arundo infestation in the early 1990s, which State Parks has been removing with good progress. Some plants are still resprouting as of October 2004, so if you can 100% positively recognize arundo, please yank out any stalks you see. (Native giant wild-rye, Leymus condensatus, can look similar, so if you can't distinguish the two, don't do it!)

The City of Carlsbad has tried to get funding to remove non-natives and revegetate with natives, but has so far been unsuccessful.

What this area really needs is for some local residents to take an interest in improving it, primarily by eliminating the invasive weeds and replacing them by natives, preferably ones grown from seed or cuttings from the remaining natives here or from nearby areas. (Planting "natives" from usual nursery sources introduces genes from plants not specifically adapted to this area, and dilutes or contaminates the local gene pool. However, the almost total lack of natural areas near this location make this less of a sin here than elsewhere.) This is a small enough area that a group of volunteers can really make a difference. (In larger areas, it is almost hopeless to try to remove invasive weeds except through very costly, long-term programs.)

Ironically, now that erosion of the slopes due to people has largely stopped, squirrel over-population, due to people feeding the squirrels, is now undermining the slope.

It was claimed (NCT 2/10/02) that the sea wall originally had 15 feet protruding above the sand level on the beach side, and that it was now 17-18 feet above the beach due to subsequent beach erosion. If so, you can measure how much sand has eroded from the beach since the wall was installed by measuring the current height of the wall above the beach. However, my recollection is that the wall isn't nearly that high above the sand, and so something either got garbled in the newspaper article, or a heck of a lot of sand has been added to the beach since then. (There has been sand replenishment since the wall was installed, but most of that was before 2002.) If any reader knows the true information here, please let me know. I'll measure its current height on my next visit.

Sources: personal observations (~1990 to 2004); NCT 2/10/02; Don Rideout (emails of 1/10/05).

By the way, directly to the north of the "trailhead", immediately south of Harbor Fish Cafe, was the (in)famous art work installed in the early 1990s, called The Split Pavilion. This art work was soon dubbed The Bars, since it consisted of jail-cell type long rods of metal. This artwork offended enough people so that Carlsbad eventually had a citywide vote that resulted in its expensive removal in the late 1990s. This is now a grassy area much used by the public. (But for the record, my young son enjoyed climbing on those bars.)

Directions to "Trailhead": Take the Carlsbad Village Drive exit from I-5, and head west on Carlsbad Village Drive until it ends at a T-junction with Ocean Street, where you are one beach house away from the Ocean. Turn left, and go just over one block to a parking lot at the beach. Parking is free. The sidewalk begins just past the southwest corner of the parking lot, immediately beyond the grassy area.

Highlights of This Trail

Number of Unique Taxa On This Trail

The following histogram gives the number of trails in our database that contain each taxon on this trail. I had 79 trails in my database when this histogram was made. A number of "1" means the taxon has only been found on this trail among the trails in my database.

Number of Trails Containing A Taxon	Number Of Taxa On This Trail	% of Taxa On This Trail
1	3	12%
2	5	19%
3	1	4%
4	1	4%
5	1	4%
1-5	11	42%
6-10	4	15%
11-15	5	19%
16-20	2	8%
21-25	1	4%
26-30	0	0%
31-35	0	0%
36-40	1	4%
41-45	2	8%
Total Taxa	26	100%

I found 7 additional species not in the above table, since they have not been identified yet. The unidentified ones are marked with ? or sp in the id? column in the guide, and have no entries in the #all column.

Fieldwork Dates and Summary of List Changes With Time

The following table gives the dates the trail was walked and taxa recorded. After each visit, the table gives the total number of taxa on the list and the breakdown of the taxa without positive identification. See Explanation of Plant Trail Guides to understand the symbols below.

Visit Date	Visit #	# taxa	# "?"	# "sp"	# "~"	# "ssp"
10/21/2002	1	20	7	2	1	1
11/4/2002	2	20	6	1	0	0
10/6/2003	3	21	0	1	1	0
10/11/2004	4	33	5	1	2	1

The first three visits only did the list for the upper sidewalk; 10/11/04 was the first time the lower sidewalk was covered. On 10/11/04, six new species were found on the previously-walked portion; six species were added on the lower portion.

The Plant Guide

Version for printing, without lines and other text on this page (2 pages)

Mile	#	id?	Common Name	Latin Name	#here	#all
0.00			Begin plant guide at southwest corner of Pine Ave and Carlsbad Blvd. This guide only lists plants on the right of the sidewalk that are easily visible from the sidewalk; one cannot necessarily touch the species from the sidewalk.
0.00	1		*natal plum	Carissa macrocarpa	3 / 2	1
0.00	2		*European sea rocket	Cakile maritima	20 / 9	2
0.00	3	~	*ripgut brome	Bromus diandrus	/ 1	41
0.00	4		*creeping Australian saltbush	Atriplex semibaccata	20 / 9	10
0.00	5		*Russian thistle	Salsola tragus	99 / 9	24
0.00	6		*marsh rosemary	Limonium perezii	10 / 5	1
0.00	7		*stock	Matthiola incana	30 / 9	2
0.00			First bench and palm tree on sidewalk.
0.00	8		coastal goldenbush	Isocoma menziesii+	99 / 9	11
0.01			Second palm tree and end of this bay in sidewalk.
0.01	9		sacred datura	Datura wrightii	10 / 9	14
0.01	10		*sea fig	Carpobrotus chilensis	10 / 2	2
0.04	11		seaside heliotrope	Heliotropium curassavicum	10 / 3	7
0.07	12	~	coast cholla	Opuntia prolifera	30 / 9	3
0.09	13		*castor bean	Ricinus communis	/	14
0.09			Second bay with benches. Jct. Walnut Ave.
0.09	14		*little horseweed	Conyza bonariensis	50 / 9	11
0.10			Lots of cholla.
0.11			A close cholla
0.13	15		saltgrass	Distichlis spicata	99 / 9	10
0.14			Pedestrian crossing to Sycamore Ave.
0.15	16		California encelia	Encelia californica	30 / 5	12
0.15			Stairs to beach.
0.18			Jct. Chestnut Ave.
0.21			Third bay with benches.
0.22	17		*red brome	Bromus madritensis ssp. rubens	/ 1	42
0.23			Stairs to beach.
0.25	18	ssp	California buckwheat	Eriogonum fasciculatum var. foliolosum	10 / 2	40
0.25			Pedestrian crossing to Maple Ave.
0.29	19	?	unk annual in habit like filago.
0.32			Fourth bay with benches. Jct. Acacia Ave.
0.34			Large water meter.
0.38			Stairs to beach and pedestrian crossing to Cherry Ave.
0.40			Fifth bay with benches, with flower planting in sidewalk that includes a tree or large shrub.
	20	?	unk annual like sweet clover (location not precise)
0.42	21		*Bermuda grass	Cynodon dactylon	50 / 5	20
0.43	22		*campground shrub	Myoporum laetum	/	2
0.45			Sixth long bay, from Juniper Ave. to Hemlock Ave.
0.48			Planted tree in grass on left of sidewalk.
0.54	23	sp	umbrella plant?	Cyperus involucratus?	10 / 1
0.55			Stairs to beach; jct. Redwood Ave.
0.55	24	?	unk annual like sweet alyssum (10/1)
0.57	25		*spotted spurge	Chamaesyce maculata	/	2
0.58	26		*giant reed	Arundo donax	/	8
0.58	27		*dallis grass	Paspalum dilatatum	/	5
0.60			Take stairs to beach (just before jct. with Tamarack Ave.), and turn right at bottom, back toward beginning of loop.
			Locations are not yet precise for the return trip along the lower beach sidewalk.
			Stairs to upper sidewalk.
	28		*tree tobacco	Nicotiana glauca	/	18
			Stairs to upper sidewalk.
	29	?	spider lily? naked ladies?	Lycoris squamigera? Amaryllis belladonna?	5 / 1
			Stairs to upper sidewalk.
	30		sea-cliff buckwheat	Eriogonum parvifolium	3 / 1	4
	31	?	subshrub with leaflet like deerweed (1/1)
			Stairs to upper sidewalk; lifeguard station #28.
	32		unknown plant with thick leaf, petiole ~ blade, elliptic blade (5/1)
	33		*prostrate myoporum	Myoporum parvifolium	5 / 1	1
1.21			Sidewalk curves right and goes uphill.
1.22			End plant guide back at the beginning.

Comments On Specific Species

Isocoma menziesii. In my experience, the subspecies are not separable in Southern California. See Comments on the Jepson Manual and A Flora of Southern California by Munz: Isocoma menziesii.

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Copyright © 2002-2005 by Tom Chester.
Permission is freely granted to reproduce any or all of this page as long as credit is given to us at this source:
http://tchester.org/sd/plants/guides/carlsbad_beach_sidewalk.html
Comments and feedback: Tom Chester
Updated 11 January 2005.