The Carsiana Botanic Garden is dedicated to the flora and natural environments of Carso. Here you can acquaint yourself with the natural and landscape characteristics of a territory of about 450 km² that extends from Italy through to Slovenia, from the seaboard to the mountains, comprising environments with very different climates and ecological characteristics. These environments have been carefully reproduced at the garden.
The Carsiana Botanic Garden has been founded in 1964 by a group of local enthusiasts, passionate about the flora of Carso. The territory of provenance of the many species present here extends from the Bocche del Timavo (in the north of the region) to the Vipacco valley, in Slovenia; from mounts Auremiano and Taiano (also in Slovenia) all the way to the Dordogna estuary, in the southern extremity of the region. Since 1972, the province of Trieste manages the garden, and in 2002 it has also acquired the property. The garden is open to the public since 1978, and over the years it has become an important hub for the divulgation of knowledge and plant culture, as well as an environmental education centre.
The Carsiana Botanic Garden is located within a doline in the municipality of Sgonico/Zgonik and occupies an area of 5,000 square metres, playing host to about 600 plant species found within the Karst area (Carso in Italian; Krst in Slovenian).
Along the footpaths in the garden the visitor can get to know the main local environments, including karstic scrubland, open dry grassland and sea-cliffs: all habitats which have been carefully reconstructed taking advantage of the micro-climatic conditions and of the geo-morphology that the site offers.
With the help of a map guide, which is given to you at the entrance (available in English too), you can discover for yourself the secrets of Carsiana Botanic Garden – such as, for example, that the location of the different species does not follow a systematic order, as each plant is placed within its own natural habitat, which have been painstakingly recreated to mimic the specific ecological characteristics found in nature (as for light, humidity, soil, etc.). The botanic classification, however, is reported on a label with the usual binomial Latin name, alongside with Italian, Slovenian and English common names. The flowering period, instead, is indicated with Roman numbers.
The Karst Geology. In the Carsiana Botanic Garden you will not only learn about plants, but you will also get to know the geology of this territory and its characteristic karstic features. The Carso region is formed, precisely, of calcareous rock, mainly composed of calcium carbonate, which is then corroded by rain, made slightly acidic by carbon dioxide in the atmosphere. The slow corrosion process creates the typical karstic phenomena, observable also in the garden; amongst them, a 9-meter deep dolina, a sunken cave, a sinkhole and some Karrenfelds (or ridged fields): these are rock outcrops with many small sharp ridges, crevices and holes.
It is advised to visit the Carsiana Botanic Garden in a clockwise direction. In this way, the visitor will encounter the following habitats:
Karstic Scrub. This is the most widespread habitat in the uplands of Carso, where it rapidly became established in the years following WW2, when the practice of grazing was abandoned. It is an environment characterised by sparse vegetation, with plants adapted to thrive on shallow, arid soil, poor in nutrients. Hop Hornbeam (Ostrya carpinifolia) and Manna (or Flowering) Ash (Fraxinus ornus) are the two most important tree species present here, and are soon joined in the succession by Downy Oak (Quercus pubescens). Common are also Field Maple (Acer campestre) and Montpelier Maple (Acer monspessulanum). The habitat is that of a sparse scrubland with plenty of light filtering, in which the shrub layer is a rich mix of Smokebush (or Sumac, Cotinus coggygria), European Cornel (or Cornelian Cherry, Cornus mas), Hawthorn (Crataegus monogyna) and St. Lucy’s Cherry (Prunus mahaleb) – from which an excellent honey can also be obtained –, whilst the field layer is dominated by Autumn Moor-grass (Sesleria autumnalis) together with Wild Peony (Paeonia officinalis), Narrow-leaved Asparagus (Asparagus tenuifolius), Istrian Hellebore (Helleborus istriacus), Mercury plant (Mercurialis ovata) and False (or White) Dittany (Dictamnus albus).
The Scree. It is made up of more or less steep limestone rubble; screes are formed at the foot of the mountain slopes and are the characteristic habitat of some parts of Carso, where they are found especially in the Val Rosandra, on Monte Nanos and on the Tarnova plateau, in nearby Slovenia. The sloping, unstable ground can only allow the growth of a sparse herbaceous vegetation, as it lacks a developed soil; the scarcity of water and of nutrients and the intense exposure to atmospheric agents and strong sunlight are its main features, so the herbaceous species found here have very deep root systems enabling them to obtain water. Their leaves have a reduced surface area, and the plants themselves display a prostrate character so to reduce transpiration. The karstic scree hosts botanical rarities such as an endemic Fescue grass (Festuca spectabilis subsp. carniolica): a plant belonging to the Graminaceae family that consolidates rubble thanks to its strong and pronged roots, Dryptis spinosa subsp. jacquiniana and Buckler-Mustard (Biscutella laevigata subsp. hispidissima). Impressive plants such as Pyramidal Bellflower (Campanula pyramidalis), and less garish but nonetheless interesting ones such as Shining Bedstraw (Galium lucidum), Common Houseleek (Sempervivum tectorum) and the endemic Illyrian Broom (Genista holopetala) can also be admired: this is a species at risk of extinction that in Italy can only be seen in the Val Rosandra.
Karstic Woodland. In ancient times the Carso was covered in an oak forest that, following deforestation and animal grazing – which were carried out for centuries –, was gradually destroyed. Just a few fragments of this ancient forest now survive, such as in the Val Rosandra and on Monte Lanaro. Here the canopy is dominated by Sessile Oak (Quercus petraea), and the field layer by Autumn Moor-grass (Sesleria autumnalis).
Dry Grassland. This habitat is called landa carsica (in Italian) or gmajna (in Slovenian), and it is basically an arid environment with protruding rocks that was created through centuries of grazing pressure by sheep and goat on deforested areas: a process that seems to have begun during the Bronze Age (c. 5,500 – 3,200 years ago), with the arrivals of shepherds in the Carso and the diffusion of pastoralism. It is mainly composed of plants that can withstand well the trampling and grazing of animals, or of species disliked by animals for their thorns, like Juniper (Juniperus communis) or Amethyst Eryngo (Eryngium amethystinum), or others still, containing irritating substances, such as the Spurge Euphorbia nicaeensis. In actual facts, for the variety of its flora, the landa carsica is an environment of great scientific value, protected at European level. It hosts an average of 40 species per square meter, and in these arid grasslands many endemic plants can also be found – such as Tormentil (Potentilla acaulis subsp. tommasiniana) or Spring-flowered Gentian (Gentiana primaticcia), but the main elements supporting the structure of the dry grassland are Rock Knapweed (Centaurea rupestris) and Dwarf Sedge (Carex humilis). These are species able to survive in arid conditions, with low soil fertility. A host of other plants can also be found in flower between March and August, including Crested Knapweed (Centaurea cristata), Illyrian Iris (Iris cengialti subsp. illyrica) and Triestine Gentian (Gentiana tergestina). Other species present in the grassland comprise the Thistle Jurinea mollis, Goldendrop (Onosma javorkae) and Mountain Pasque Flower (Pulsatilla montana). The grassy sward is dominated by Dwarf Sedge (Carex humilis), but Steppe-grass (Stipa eriocaulis) is also present.
The Coastal Cliffs. The south-facing nature of the northern slope of the garden has allowed it to be planted with some of the species that characterise the coastal strip of Carso within the province of Trieste between Duino and the Grignano cliffs – suspended above the sea and thus exposed to the strong sun, while equally sheltered from the cold bora winds – but also typical of Dalmatia and the Qvarner Gulf (Golfo del Quarnaro), where the vegetation is mainly represented by Mediterranean scrub and woodland. This type of vegetation – of which Evergreen (or Holm) Oak (Quercus ilex) is typical, together with other sclerophyllous evergreens such as Bay Tree (Laurus nobilis), Broad-leaved Phiillyrea (Phiillyrea latifolia), Laurustinus (Viburnum tinus), Wild Madder (Rubia peregrina) and Etruscan Honeysuckle (Lonicera etrusca) – mostly developed between 5000 and 3000 BC, when the climate was drier and also 2-3 degrees warmer than now. When the climate became fresher, this vegetation survived only in the locations with a warmer microclimate, therefore today it is described as a floral relic. The coastal vegetation includes showy species such as Pyramidal Bellflower (Campanula pyramidalis) and Wulfen’s Spurge (Euphorbia wulfenii), as well as aromatic and/or spiny plants such as Common Sage (Salvia officinalis), Turpentine Tree (Pistacia terebinthus), Myrtle (Myrtus communis), Christ’s Thorn (Paliurus spina-christi) and Wild Asparagus (Asparagus acutifolius).
Ponds in the Karst. One of the most unusual but typical features of the karstic environment is the almost complete absence of surface water. This is mainly due to the permeability of the rock substrate, which is full of holes and fissures; the water tends to run along underground streams, leaving the surface without aquatic habitats. Natural wetlands are therefore rare in the Carso, with the only exception of the lakes of Doberdò and Pietrarossa; there are, however, some ponds that were created by man. These ponds – small depressions in the ground in which the storage of water is favoured by the bringing in of clay – were used for the watering of livestock and to provide drinking water for local people. In the artificial ponds present at Carsiana Botanic Garden, the visitor can admire wetland species that are characteristic of these environments, such as Yellow-Flag Iris (Iris pseudacorus), Yellow Loosestrife (Lysimachia vulgaris), Purple Loosestrife (Lythrum salicaria) and Fen Ragwort (Senecio paludosus), which occupy the parts that are only periodically exposed. The banks of the pond, on the other hand, play host to the Rushes Juncus inflexus and J. articulatus. The areas that are normally submerged host plants like Common Reed (Phragmites australis) and Common Bulrush (Typha latifolia), while in the deeper parts of the pond those species with floating leaves – such as White- (Nymphaea alba) and Yellow Water Lily (Nuphar lutea) – can be seen.
The Upland Karst. The species gathered in this part of the garden are representative of the Carso hinterland, which is higher in altitude, where the cooler climate and greater rainfall amounts, as well as more frequent snowfalls, allow the development of beech woods. These conditions of coolness and high humidity are recreated along the garden’s southern edge by using an interconnected system of little channels and pools, covered in stone chippings and earth – evaporation from which cools the upper layers of soil, thus allowing species such as Hairy Alpenrose (Rhododendron hirsutum), Dwarf Alpenrose (Rhodothamnus chamaecistus), Mountain Avens (Dryas octopetala), Carniolan Primrose (Primula carniolica) and Henbane Bell (Scopolia carniolica) to thrive. Amongst the most notable plants here one must include Martagon Lily (Lilium martagon) and a precious orchid, Cypripedium calceolus, also known as Lady’s Slipper Orchid.
The Doline Woodland. The dolines – or sink-holes – are one of the most notable formations in karstic topography. These are enclosed depressions which are formed by the dissolving of calcareous rock through the action of naturally acidic rainwater over fissures or cracks in the bedrock; at the bottom are often found the sink-holes, or proper caves. The dolines are characterized by the phenomenon of temperature inversion; the temperature declines as one descends further into the doline (normally it is the other way around): the cool air remains trapped at the bottom, thus creating a micro-climate that is cooler than in the rest of the surrounding Carso. As a result, where cool and humid air stagnates, a typical woodland is formed, known as Asarum-carpinetum, whose flora presents species that are usually found at higher altitudes. The dominant trees here include Common Hornbeam (Carpinus betulus), Hazel (Corylus avellana), Sessile Oak (Quercus petraea), Turkish Oak (Quercus cerris) and Small-leaved Lime or Linden (Tilia cordata). The field layer comprises Asarabacca (or European Wild Ginger, Asarum europaeum), but also many herbaceous plants that blossom as early as March, such as Green Hellebore (Helleborus odorus var. istriacus), Dog’s Tooth Violet (Erythronium dens-canis), Spring Vetchling (Lathyrus vernus), Wood Anemone (Anemone nemorosa), Rue-leaved Isopyrum (Isopyrum thalictroides) and Alpine Squill (Scilla bifolia).
The Karstic Pot-Hole. The bottom of the doline, on its southern edge, has a pot-hole – the entrance to which is broad and roughly circular (7 x 7 m) – which allows the observer to examine the vertical walls that drop away to a ledge sticking out 17 m below. The base of the first sink-hole is at 23 m, while the cavity continues winding its way down to a depth of 39,5 m, but the doline bottom is secluded to the sight by the aforementioned rocky spur; all in all, this can be considered a vertical cavity with a double well. On the pot-hole walls characteristic species such as Hart’s Tongue Fern (Phyllitis scolopendrium), with elongated leaves, or Common Polypody (Polypodium vulgare) – as well as several mosses – can be seen: all plants that need very little light. Further into the pot-hole there are more mosses, the most abundant of which is Thamnium alopecurum, whilst even further into the darkness there is just a patina of green and blue-green algae.
Since 2013, the Carsiana Botanic Garden also contains a new part: the Mediterranean Garden. This section has been placed within a context of high environmental interest; the area, in fact, is located on the rim of the dolina – an unusual morphological structure, typical of the Karst zone, normally associated with caves and spots where surface water drains away quickly. The coastal strip of Carso near Trieste – together with the ridge overlooking it – represents a sort of gateway to the Mediterranean, with the most northerly part of its basin corresponding to the far northern end of the distribution area of Mediterranean vegetation. Furthermore, the biodiversity characterising all Karst areas is unusual, and of remarkable scientific and educational interest. This is the leading principle which has been inspiring the implementation of Carsiana Botanic Garden since its foundation. The new section gathers together both the Mediterranean plants of the Carso region and those typical of more southerly areas nearby, where the natural environment conditions are drier and where we can find, for example, plants such as Myrtle (Myrtus communis) and Strawberry Tree (Arbutus unedo), together with different species of Rockrose (Cistus sp.).
A visit to the Carsiana Botanic Garden is advised at all times of the year from late spring to late autumn, bearing in mind that the opening times are seasonal and must be checked before coming. The best time to visit in order to see the majority of plants in blossom, however, is late spring/early summer, before the hot and dry period sets in; then again late summer/early autumn for some very showy species – such as the majestic Pyramidal Bellflower (Campanula pyramidalis).