REINFORCE SITE WITH VEGETATION
| On a single site or throughout a neighborhood, vegetation is the leading component in green infrastructure. This strategy describes the properties of soil, elevation, and plant types that are necessary for vegetation to serve as a protective element. | Strategy in Action 1. Identify Soil Type and Properties 2. Choose and Plant Vegetation 3. Implement Resilient Sitescaping |
WHAT YOU NEED TO KNOW
The success of vegetation depends on:
- Appropriateness of plant for soil type
- Health of plants and plant properties
- Maintenance and care
- Available light
Benefits of vegetation include:
- Soil stabilization
- Restoration of local ecosystems
- Creation of recreational spaces
- Shading and wind break
- Air and water quality enhancement
- Potential source of food or medicine (see Strategy 3: Plant an Edible Garden)
A. TYPE
There are several factors that determine the type of soil in an area: composition, climate, topography, plant activity, and minerals. The consistency of the soil can be classified as silt, sand, or clay. Sandy soil is found in rivers and beaches and is very loose and easy to work with, but has few of the nutrients that a plant may need. Silt is fertile and easy to work with. Clay has small particles and is very heavy when wet, making it difficult to work with. The combination of the three soil types—that is very fertile—is known as loam.
IDENTIFY TYPE OF SOIL BY REGION
The consistency of soils naturally occurs as a mixture of the different kinds, as illustrated to the right.
The soils in Puerto Rico are variable and are classified as different types or diverse series depending on their localization within Puerto Rico. The soils that have similar characteristics conform a series. The most prominent series were classified in 11 groups. The two principal groups are in the mountainous and humid regions and the coastal valleys. The set of these series is known as the association, named after the areas in which they were identified. In the mountainous humid area, the associations include Tanamá-San Sebastián, Humatas-Los Guineos-Alonso, and Pellejas-Lirio-Ingenio; these are clay-like and loamy.
B. PROPERTIES
Properties of soil will vary based on location in the island, the relationship to coastal and water resources, altitude, and the proximity to developed communities. It’s important to pay attention to the following elements as soil is selected.
- Salinity: A measure of the concentration of salts in water or soil.
- PH Balance: Measures the acidity or alkalinity of water or soil. The scale of PH is logarithmic and goes from 0 to 14. A PH of 7 is considered neutral.
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Contamination: Laboratory tests can be performed to detect contaminants in the composition of the soil.
- Subsoil: The layer just below the topsoil, which has less organic matter in its composition.
Native trees are those that are part of the natural landscape of Puerto Rico. Native trees are better at sustaining the local climate and may also have more capacity to survive extreme events like Hurricanes Irma and Maria.
- Choose vegetation based on your results from the chart above, the landscape available, and your intended purpose.
- Consult with agronomists, gardeners, or municipality agriculture experts about uses, recommendations, maintenance, and the resistance of trees under hurricane winds.
- Before covering an entire area with plants, test a small section and ensure that the plant is growing well without damaging the soil. If the test is not successful, move the plant to a different location or try another plant.
- Although they provide shade, it is best not to plant medium to big trees at a distance where they can fall on a home if toppled by hurricane winds. Nearby trees can also increase the humidity inside the home and can encourage mold growth.
- Plant trees in places that match its preferred conditions so that they won’t need excessive care, like watering or adding nutrients. Consider the use compost to fertilize.
- Consult an arborist or an agronomist in case the tree has signs of a disease or insects.
- Consider the use of natural insecticides.
SEASHORE DROPSEED
SPOROBOLUS VIRGINICUS
DESCRIPTION
A spreading perennial with green or purple flowers. Grows from 10 to 50 cm (4 to 20 inches).
SOIL CONDITIONS REQUIRED
- Soil Type: Sandy (stable dunes)
- Salinity: High
BENEFITS
- Dune stabilization
- Provides habitat for animal species.
SALT HAY
SPARTINA PATENS
DESCRIPTION
Grass grown from 1 to 5 feet tall solitary or in small clumps.
SOIL CONDITIONS REQUIRED
- Soil Type: Sandy
- Growns on low dunes or sand flats
- Salinity: High
BENEFITS
- Dune stabilization
- Provides habitat for animal species
STRONGBARK
BOURRERIA SUCCULENTA
DESCRIPTION
Small to medium tree with green leaves arranged alternately, and it has fruit that goes from orange to red when ripe.
SOIL CONDITIONS REQUIRED
- Soil Type: Occurs in sand with a limestone substrate
- Salinity: Moderately tolerant to salt
- pH: High
BENEFITS
- Attracts pollinators and provides food for birds.
BEACH BEAN
CANAVALIA MARITIMA
DESCRIPTION
A perennial herb with a trailing or climbing stem
SOIL CONDITIONS REQUIRED
- Soil Type: Sandy Grows along coasts and edges of coastal bushland
- Salinity: High
BENEFITS
- Dune stabilization
- Provides habitat for animal species
- Can form a symbiotic relation with bacteria in the soil that enriches the soil.
SEA GRAPE
COCCOLOBA UVIFERA
DESCRIPTION
Medium tree that grows on the coasts. The tree has big rounded leaves and produces edible fruits.
SOIL CONDITIONS REQUIRED
- Soil Type: Sandy
- Salinity: High
BENEFITS
- Can be used as a hedge and wind breaker and shadig system.
- Tolerates drought.
ALLIGATOR WEED
ALTERNANTHERA PHILOXEROIDES
DESCRIPTION
Aquatic (freshwater). Often forms tangled masses in water. Good in shallow ponds, depressions, and ditches with fresh water. Considered invasive.
SOIL CONDITIONS REQUIRED
- Soil Type: Water (damp soil)
BENEFITS
- Can be used to stabilize soil and sites.
- Considered invasive and must be restrained to control its growth.
WATER LILY
NYMPHAEA AMPLA
DESCRIPTION
Aquatic (freshwater) plant that floats with a submerged root. Flowers are white and diurnal.
SOIL CONDITIONS REQUIRED
- Soil Type: Water (damp soil)
- Salinity: Freshwater
BENEFITS/ RISKS MITIGATED
- Provides habitat for animal species.
- Can be invasive.
WATER HYSSOP
BACOPA MONNIERI
DESCRIPTION
Aquatic (freshwater) succulent with leaves and small white or light blue flower.
SOIL CONDITIONS REQUIRED
- Soil Type: Water
BENEFITS/ RISKS MITIGATED
- Provides nesting and food for birds.
SOUTHERN CATTAIL
TYPHADOMINGENCIS
DESCRIPTION
Forms extensive colonies. Grows in rivers, beside lakes and herbaceous marshes.
SOIL CONDITIONS REQUIRED
- Soil Type: Water (damp soil)
- Salinity: Freshwater
BENEFITS/ RISKS MITIGATED
- Provides habitat and nesting sites for birds.
- Can be invasive.
BLACK OLIVE TREE
BUCIDA BUCERA
DESCRIPTION
A medium to large tree which can grow up to 100 feet.
SOIL CONDITIONS REQUIRED
- Soil Type: Can grow almost all over the island, in both humid and dry soils.
BENEFITS
- It can be planted to embellish and to provide shade. It is a large tree, so care must be taken when planting it near structures.
WHITE CEDAR
ABEBUIA HETEROPHYLLA
DESCRIPTION
A medium tree that can reach 60 feet. Its flowers are pink and tubular. Its delicate white seeds can be dispersed by the wind.
SOIL CONDITIONS REQUIRED
- Soil Type: The tree grows in the woods along the island.
BENEFITS
- It can grow in almost any type of soil and can be used for embellishment for parks.
ROYAL PALM TREE
RYSTONEA REGIA
DESCRIPTION
A palm tree that can reach 30 meters in height and has a distinctive sheath on the upper part of its foliage.
SOIL CONDITIONS REQUIRED
- Soil Type:
- Can grow in dry and humid soils.
- Common in the humid mountains.
BENEFITS
- Decorative; its fruit is an important source of food for birds and insects.
- Dry leaves that fall from the tree can be dangerous for cars and people.
ROYAL POINCIANA
DELONIX REGIA
DESCRIPTION
A medium tree distinctive for its showy red flowers and umbrella-like canopy.
SOIL CONDITIONS REQUIRED
- Soil Type: Will grow in almost any soil but needs good drainage, will tolerate drought.
- Salinity: Will tolerate salt.
BENEFITS
- Care must be taken when planting near homes because the root system will damage foundations or anything near it that is underground.
MANILA PALM
ADONIDIA MERRILLII
DESCRIPTION
A palm tree that can reach 20 feet high. Its fruit is distinctive and is important for bird species.
SOIL CONDITIONS REQUIRED
- Soil Type: Fertile soils with good drainage.
BENEFITS
- Used for embellishment and its fruit is an important source of food for bird.
JUNGLE GERANIUM
IXORA COCCINEA
DESCRIPTION
A shrub with very dense foliage, showy red flowers, and dark purple fruit. Its flowers attract bees and birds.
SOIL CONDITIONS REQUIRED
- Needs full sun but can tolerate some shade.
BENEFITS
- Can be used as a hedge.
NARRA
PTEROCARPUS INDICUS
DESCRIPTION
A large tree with many long branches, yellow flowers, and a distinctive round wing seed.
SOIL CONDITIONS REQUIRED
- Soil Type: Can be found in various types of soils, from sandy loams to clay.
- Salinity: Tolerates moderate levels of salt in the soil.
BENEFITS/ RISKS MITIGATED
- A nitrogen-fixing tree, it has been recommended for use in agroforestry systems and as a shade tree for coffee and other crops
TEA
AMYRIS ELEMIFERA
DESCRIPTION
Grows from a shrub to a small tree up to 6 meters in height. The leaves are aromatic when crushed. It has white flowers and bears fruit.
SOIL CONDITIONS REQUIRED
- Soil Type: Grows well in sandy soils and limestone soils. Can also grow in moist terrains with good drainage.
- Can be found in the Guanica Dry Forest.
BENEFITS/ RISKS MITIGATED
- Its fruit is a source of food for birds.
- The tree is very resinous, and its wood can be used as a torch.
WEST INDIAN SATINWOOD
ZANTHOXYLUM FLAVUM
DESCRIPTION
Grows from a shrub to a small tree up to 11 meters in height. The leaves are aromatic when crushed and its flowers are a greenish white color.
SOIL CONDITIONS REQUIRED
- Soil Type: Can grow in a sandy terrain and limestone.
- Can be found in the Guanica Dry Forest.
BENEFITS/ RISKS MITIGATED
Its flowers attract pollinators (insects and bees).
MANGROVES
DESCRIPTION
- Also known: Button Mangrove, White Alling, Black Mangrove, Red Mangrove, White Mangrove
- Mangroves can survive on the threshold of water and terrain on the coast but are not limited to it.
SOIL CONDITIONS REQUIRED
- Soil Type: Water (damp soil) and sand in coastlines and estuaries
- Salinity: High
- Can also be found in estuarine waters.
BENEFITS/ RISKS MITIGATED
- Mangroves are known as nature’s filters; the reason they have a distinctively sour smell is precisely because they cycle pollutants out of the water. Because of their high tolerance for varying levels of salinity and strong root systems, they are fantastic to use as natural sea walls or rompeolas against wave surges and for any type of shore suffering from erosion.
BLACKRODWOOD
EUGENIA BIFLORA
DESCRIPTION
Small to medium tree with green leaves of 1 - 2 cm and small white flowers. Gives small fruit that is red or black when ripe.
SOIL CONDITIONS REQUIRED
- Soil Type: Can be found in the coastal valleys, limestone substrate, and in the mountains.
BENEFITS/ RISKS MITIGATED
- Provides fruit for birds.
SERRETTE GUAVE
EUGENIA DOMINGENSIS
DESCRIPTION
- Small to medium tree with green leaves and white small flowers. Gives small round fruit which is red when ripe.
SOIL CONDITIONS REQUIRED
- Soil Type: Can be found in mountains, humid mountains, and coastal valleys.
BENEFITS/ RISKS MITIGATED
- Provides fruit for birds.
WEST INDIAN BAY TREE
PIMENTA RACEMOSA
DESCRIPTION
Small to medium tree with aromatic leaves.
SOIL CONDITIONS REQUIRED
- Soil Type: Can be found on hillsides but can grow in somewhat humid areas
BENEFITS
- Its leaves are used to make an infusion with rubbing alcohol to relieve muscular pain (alcoholado).
MAGA
THESPESIA GRANDIFLORA
DESCRIPTION
A small to medium tree with large green leaves and a red to dark red flower.
SOIL CONDITIONS REQUIRED
- Soil Type: Grows best in limestone hillsides and alluvial bottom between the hills.
- Can grow in full sun and some shade.
BENEFITS
- Attracts pollinators and can be used for shade and embellishment in parks.
BLACK CALABASH
AMPHITECNA LATIFOLIA
DESCRIPTION
Small to medium tree can reach 30 feet with a variable spread.a narrow crown, is moderately dense and of irregular form. Gives yellow flowers and green fruit.
SOIL CONDITIONS REQUIRED
- Soil Type: The soil found in the coastal line.
- Needs open space and good sun.
BENEFITS
- This upright, densely-foliated, evergreen can provide site shading and stabilization. Provides food for birds.
FIDDLEWOOD
CITHAREXYLUM FRUTICOSUM
DESCRIPTION
A small to medium tree with extended top, irregular foliage and white flowers. It gives abundant fruit.
SOIL CONDITIONS REQUIRED
- Soil Type: Can tolerate humid and somewhat dry soils.
BENEFITS/ RISKS MITIGATED
- Provides food for birds and attracts bees.
MARICAO
BYRSONIMA SPICATA
DESCRIPTION
A medium tree with green leaves, though some are red, and others are yellow. The Maricao has yellow flowers and gives fruit irregularly through the year.
SOIL CONDITIONS REQUIRED
- Soil Type: Does not tolerate humid soils.
- Needs good sun
BENEFITS/ RISKS MITIGATED
- Provides food to pollinators, including bats and birds.
- Plant trees in places that match its preferred conditions so that they won’t need excessive care, like watering or adding nutrients. Consider the use compost to fertilize.
- Consult an arborist or an agronomist in case the tree has signs of a disease or insects.
- Consider the use of natural insecticides.
When planting vegetation that will need a minimum of care and maintenance, it’s better to choose local vegetation, the ones that grows better within the conditions of the place where they will be planted.
A. GREEN ROOFS
Roofs that are partially or completely covered with vegetation and a growing medium mitigate excessive heat gain and manage stormwater.- Green roofs are classified according to the depth of soil or growing medium, which determines species it can support.
- A green roof consists of several layers including a membrane to protect the roof from water leakage, soil layers, a drainage layer and vegetation.
- Consult with building professionals to identify the load a roof can sustain with plantings, water and materials.
- Verify that roof vegetation is watered to prevent building flammability and maintain ability for roof habitat and benefits. This may require water pumped to the roof.
Roofs that are partially or completely covered with vegetation and a growing medium mitigate excessive heat gain and manage stormwater.
EXTENSIVE
- Does not require an irrigation system (thin soil layer).
- Recommended vegetation: succulents, cacti
- Pros: minimal maintenance required,
- Relatively inexpensive
- Cons: limited choice of plants, cannot grow vegetative species
INTENSIVE
- Requires irrigation systems (thicker soil layer).
- Recommended vegetation: virtually any plant or tree whose root system will not grow deeper than growing medium (generally less than 6 inches).
- Pros: can incorporate a greater variety of vegetation
- Cons: greater weight loading on roof, higher cost
B. XERISCAPING
- A type of garden that requires little supplemental water. Creates breeze for areas that are very hot and do not receive much rain, such as Southern Puerto Rico.
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XERISCAPING
Drought-resistant landscaping needs no irrigation and thrives without almost any maintenance.
- The height of a tree must not be longer than its distance to a structure so that the tree won’t fall over said structure in case high winds overthrow it. Planting trees near homes also has the disadvantage of possibly damaging the structure of the home or damaging plumbing or service lines.
- Trim dead branches so that they won’t turn into projectiles. Consider trimming all tree branches so that they won’t exert resistance to the winds and survive hurricane winds. Trimming trees may require the work of a professional and the use of a crane or a bucket crane truck.
- Do not trim any branches by any near electrical lines. Call the authorities for that purpose whenever you see branches growing near or towards the lines. Do not plant trees near electrical lines.
- To cut a tree, obtain a permit from the Department of Natural and Environmental Resources (DRNA, by its Spanish acronym).
