Plant science or botany covers a part of the biology lessons in the educational program, but in comparison with the topic of animals it is less interesting for the students, which is reflected in a lack of interest in learning and a lack of knowledge. Practical work has an important place in teaching natural sciences. It can be included by teachers in their teaching as a basic method for acquiring knowledge or as an example of illustrating theoretical content. We did not find information on which of the two approaches is more effective when teaching about plants. Therefore, in our study, we compared how these approaches affect students' knowledge of plant reproduction and propagation, and their attitudes toward plants. We designed a questionnaire that also included a knowledge test. The survey included second year students from one upper secondary school in Ljubljana who completed the survey questionnaire twice. The questionnaire was completed before and one week after instruction. Our sample consisted of 114 students, who formed two groups that differed in applied teaching methods sequence. In both groups, lessons were taught as a block lesson. In the first group, a frontal teaching was followed by a method of practical work in the form of an labwork following pre-written instructions. In the second group, the sequence of lessons was reversed. After the statistical analysis of the data, no significant differences in students' knowledge emerged after the lessons regarding teaching methods sequence. After class, all students showed more knowledge than before class. The first group of students achieved slightly better results, but these differences are small. We found that students do not differentiate between the concepts of plant reproduction and propagation. Most students have difficulty recognizing the parts of a seed and its role, and they are not able to relate this to sexual reproduction. No significant gender differences were detected in students knowledge. After class, most students distinguished between pollination and fertilization. Although students were aware of the importance of plants in nature and of environmental pollution and are concerned about excessive deforestation, their interest in learning about plants was rather low. They find the lessons about plants boring and they prefer to learn about animals. We believe that their attitudes and knowledge can be improved primarily by incorporating direct experience with plants. Through direct experiences, students would learn about plants and their functioning, and at the same time they could develop positive attitudes toward plants and nature.