# Phenological Stages of the Species Jacaranda mimosifolia D. Don. According to the Extended BBCH Scale

## TL;DR

This study describes the seasonal growth stages of the jacaranda tree in Mediterranean climates using a standardized scale and calculates the heat needed for its annual cycle.

## Contribution

The study provides the first detailed phenological description of Jacaranda mimosifolia using the BBCH scale and quantifies its thermal requirements.

## Key findings

- Jacaranda completes its annual cycle after accumulating about 3800 growing degree-days (GDD).
- Thirty-nine secondary stages were identified across seven principal growth stages using the BBCH scale.
- The phenological framework aids in improving management practices for jacaranda in Mediterranean climates.

## Abstract

Jacaranda mimosifolia D. Don. is a popular ornamental tree widely planted in Mediterranean cities for its attractive foliage and purple flowers. However, its seasonal development has never been formally described under these environmental conditions. In this study, we monitored jacaranda trees throughout the year and identified their main growth phases using the standardized BBCH phenological scale. We also calculated the amount of heat required for the species to progress from winter dormancy to leaf fall, known as growing degree-days (GDD). Our results show that jacaranda completes its annual cycle after accumulating about 3800 GDD, indicating that it grows successfully in Mediterranean climates. This information can help improve management practices in ornamental plantings and support decisions regarding the potential use of jacaranda in experimental or agroforestry cultivation systems.

The jacaranda (Jacaranda mimosifolia D. Don.) is a widely cultivated ornamental tree species in urban landscapes, but recent research has highlighted its additional ecological and industrial potential. However, no detailed phenological description has been available for this species. The objective of this study was to establish a standardized phenological scale for Jacaranda mimosifolia D. Don. based on the BBCH coding system and to determine the thermal requirements (growing degree-days, GDD). Thirty-nine secondary stages were used to describe the life cycle of jacaranda in this BBCH scale, distributed across seven principal growth stages (PGSs). Of these thirty-nine secondary stages, five stages correspond to dormancy and sprouting (PGS-0), six stages correspond to leaf development (PGS-1), three correspond to the emergence of the flowering organ (PGS-5), eight correspond to flowering (PGS-6), ten correspond to fruit formation (PGS-7), three correspond to ripening fruit (PGS-8), and four correspond to the beginning of dormancy (PGS-9). Thermal integral analysis indicated that jacaranda requires approximately 3800 accumulated degree-days (GDD) to progress from dormancy to leaf fall. This phenological framework enhances understanding of the growth cycle of Jacaranda mimosifolia D. Don. and provides a useful reference for improving the timing and efficiency of management and phytosanitary treatments in Mediterranean conditions.