<VirtualHost *:80>
    ServerName domain.org
    ServerAlias www.domain.org

    ProxyPass /blog !
    Alias /blog /var/apache-vhosts/www.domain.org-blog

    <Directory /var/apache-vhosts/www.domain.org-blog/>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn
    CustomLog ${APACHE_LOG_DIR}/access.log combined


    ProxyPass / http://localhost:8884/
    ProxyPassReverse / http://localhost:8884/
    ProxyPreserveHost on
    LogLevel debug
</VirtualHost>

Source: node.js – how to achieve an apache Alias with a proxy pass on the same domain – Stack Overflow